kihonryoukin ga agatta ue ni, entairyoukin made aru.

In this sentence, うえに means on top of that, in addition, or to make matters worse.

So:

• 基本料金が上がった = the basic fee went up
• うえに = on top of that
• 延滞料金まである = there are even late fees

A key point is that うえに often adds another point of the same general direction. Here, both points are negative from the speaker’s perspective:

• the basic fee increased
• there are even late fees

So the feeling is something like: The basic fee went up, and on top of that, there are even late fees.

Because うえに attaches to a plain form, and here the speaker is treating the fee increase as a completed fact:

• 上がった = went up / has increased

So 上がったうえに means it went up, and on top of that...

If you said 上がるうえに, it would sound more like a general or future statement depending on context, which is less natural here.

Compare:

• 値段が上がったうえに、量も減った。
  The price went up, and on top of that, the amount decreased.

The past form before うえに is very common when the first event/state has already happened.

No. Here it does not mean after in a time-sequence sense.

Even though 上がった is past tense, うえに is not saying:

• After the basic fee went up, there were late fees

Instead, it is listing an additional negative point:

• The basic fee went up, and on top of that, there are even late fees

This is an important distinction.
うえに is about addition, not simple chronological order.

Here, まで means even.

So 延滞料金まである means:

• there are even late fees
• there are late fees too, of all things

It adds a feeling of surprise, emphasis, or frustration.

This is different from the more basic meaning of まで as until.
In this sentence, it is the emphatic even usage.

Examples of similar usage:

• お金まで取られた。
  They even took my money.
• 子どもまで知っている。
  Even children know that.

が marks 基本料金 as the subject of 上がった.

So:

• 基本料金が上がった = the basic fee went up

This is the natural pattern with intransitive verbs like 上がる:

• 値段が上がる = the price rises
• 気温が上がる = the temperature rises

You would not normally say 基本料金を上がった.

You could say 延滞料金がある, and it would simply mean there are late fees.

But 延滞料金まである adds emphasis:

• 延滞料金がある = there are late fees
• 延滞料金まである = there are even late fees

So the version with まで sounds more emotional or critical, as if the speaker thinks this is one more unpleasant thing.

延滞料金 means a late fee or overdue charge.

Breakdown:

• 延滞 = delay, overdue status, being late in returning/paying
• 料金 = fee, charge

You often see 延滞 with things like:

• library books
• rentals
• bills
• payments

So 延滞料金 is the extra fee charged when something is overdue or returned/paid late.

Yes. It is the ordinary ある used for inanimate things.

Here, 延滞料金まである literally means:

• there even exists a late fee

In natural English, that becomes:

• there are even late fees

Because 延滞料金 is not a living thing, Japanese uses ある, not いる.

Because まで is taking that slot in the sentence.

In a simple sentence, you might say:

• 延滞料金がある = there are late fees

But when まで is used for emphasis, it directly attaches to the noun:

• 延滞料金まである = there are even late fees

So まで replaces where が might otherwise appear.

It sounds like a complaint or criticism.

The speaker is presenting two negative facts:

1. 基本料金が上がった = the basic fee increased
2. 延滞料金まである = there are even late fees

Because of うえに and especially まで, the sentence has a strong feeling of:

• not only that, but also...
• to make things worse...
• and it doesn’t stop there...

So it is not just neutral information. It suggests dissatisfaction.

Yes, that is a very natural translation.

Other good translations include:

• The basic fee went up, and on top of that, there are even late fees.
• The base charge has increased, and to make matters worse, there are even late fees.
• Not only has the basic fee gone up, but there are late fees too.

The exact English wording can vary, but the key ideas are:

• an increase happened
• an additional negative point is being added
• まで adds even

They all can connect multiple points, but the nuance is a little different.

• うえに = on top of that / in addition
  Often feels a bit more formal or written, and often emphasizes piling on another point.
• し = and / plus
  More conversational and flexible.
• だけでなく = not only ... but also ...
  More explicitly structured.

For example:

• 基本料金が上がったうえに、延滞料金まである。
  The basic fee went up, and on top of that, there are even late fees.

• 基本料金が上がったし、延滞料金もある。
  The basic fee went up, and there are late fees too.

• 基本料金が上がっただけでなく、延滞料金まである。
  Not only did the basic fee go up, but there are even late fees.

All are possible, but うえに works especially well when the speaker feels the bad points are stacking up.

It usually means something like basic fee, base charge, or basic rate.

The exact English depends on context:

• phone plan
• subscription
• service contract
• utilities
• membership

So 基本料金 is the standard fixed charge before any extra costs.
That is why it contrasts naturally with something like 延滞料金, which is an additional penalty-type fee.

Yes, that is a very useful way to remember it.

This sentence follows:

• A = 基本料金が上がった
• うえに = on top of that
• B = 延滞料金まである

So:

• A うえに B = A, and on top of that, B

That pattern is very common:

• 彼は頭がいいうえに、親切だ。
  He is smart, and on top of that, kind.
• 雨が降ったうえに、風も強かった。
  It rained, and on top of that, the wind was strong.

So yes, treating it as a set pattern is a good idea.