Η εξυπηρέτηση πελατών εξηγεί την υπέρβαση ορίου δεδομένων.

The subject is Η εξυπηρέτηση πελατών.

The head noun is εξυπηρέτηση, which means service or support.
Because it is in the nominative singular, it is the thing doing the action.

So the sentence is saying that customer service is the one that explains something.

Because Greek often uses the genitive after a noun to show a relationship like of.

So:

• εξυπηρέτηση = service
• πελατών = of customers

Literally, εξυπηρέτηση πελατών means service of customers, but in natural English that becomes customer service.

This is very common in Greek. English often uses one noun in front of another, but Greek often uses a genitive noun instead.

These are both forms of the definite article the, but they show different cases.

• η = feminine singular nominative
• την = feminine singular accusative

So:

• Η εξυπηρέτηση = the customer service as the subject
• την υπέρβαση = the overage / the exceedance as the direct object

Greek articles change form depending on the job the noun does in the sentence.

εξηγεί is the 3rd person singular present tense of εξηγώ, meaning to explain.

So it means:

• he/she/it explains
• or sometimes is explaining, depending on context

Here it matches the singular subject Η εξυπηρέτηση πελατών.

Greek usually does not need a separate subject pronoun like it, because the verb ending already shows the person and number.

Because the verb agrees with the head noun of the subject, not with every noun inside the phrase.

The subject is:

• Η εξυπηρέτηση πελατών

The main noun there is εξυπηρέτηση, and that is singular.
So the verb is also singular:

• εξηγεί = explains

The word πελατών is just modifying εξυπηρέτηση. It does not control the verb.

Because it is the direct object of the verb εξηγεί.

The structure is:

• Η εξυπηρέτηση πελατών = subject
• εξηγεί = verb
• την υπέρβαση ορίου δεδομένων = object

So υπέρβαση has to be in the accusative singular, which is why we get την υπέρβαση.

It is a noun phrase built with the genitive:

• όριο = limit
• ορίου = of limit / of the limit
• δεδομένων = of data

So:

• ορίου δεδομένων = of data limit
• more naturally in English: of the data limit or data-limit

And the whole object is:

• την υπέρβαση ορίου δεδομένων = the data-limit overage / the exceeding of the data limit

This is a compact, formal Greek noun phrase.

This is a good question, because English speakers often expect something like του ορίου δεδομένων.

In Greek, especially in formal, technical, or compact expressions, a genitive noun can sometimes appear without an article and function almost like an English noun modifier.

So υπέρβαση ορίου δεδομένων is a compact expression, roughly like data-limit overage.

If you said την υπέρβαση του ορίου δεδομένων, that would sound more explicitly like the exceeding of the data limit. In many contexts, that version may feel more fully spelled out.

So the version in your sentence is not about a different basic meaning; it is more about a compact style.

Because δεδομένα is normally a plural-form noun in Greek, even when English simply says data.

Its dictionary form is:

• το δεδομένο = datum / given item
• τα δεδομένα = data

So in the genitive plural, it becomes:

• δεδομένων = of data

That is why Greek says όριο δεδομένων for data limit.

Yes. Greek word order is more flexible than English because the case endings help show what each word is doing.

The neutral order here is:

• Η εξυπηρέτηση πελατών εξηγεί την υπέρβαση ορίου δεδομένων.

But you could also move things around for emphasis, for example:

• Την υπέρβαση ορίου δεδομένων την εξηγεί η εξυπηρέτηση πελατών.

That puts more focus on the overage.

Even when the order changes, the articles and case forms still show which noun is the subject and which is the object.

Not always exactly, but it is often used that way in practice.

Literally, εξυπηρέτηση πελατών means customer service or customer support.
Depending on context, it can refer to:

• the function of customer service
• the customer service team
• the customer service department

If you wanted to be more explicit, you could say:

• το τμήμα εξυπηρέτησης πελατών = the customer service department

So the shorter phrase can be slightly broad, just like English customer service.

It can mean either, depending on context.

The Greek present tense often covers both:

• a general present: explains
• an ongoing present: is explaining

So without more context, εξηγεί could mean either one.

English forces you to choose more often than Greek does, but Greek often leaves that to context.