Kanselahin ang mobile plan sa customer service.

Because this sentence is a command/instruction. Filipino often puts the verb first, especially in simple commands.

• Kanselahin = Cancel it / Cancel that
• So the full sentence is structured like: Verb + thing affected + location/contact point

This is normal Filipino word order.

Kanselahin comes from kansela (from cancel) plus the suffix -hin.

In this sentence, -hin helps make the verb object-focused, meaning the sentence highlights the thing being acted on — here, the mobile plan.

So:

• kansela = cancel
• kanselahin = cancel something

In an imperative sentence, it means Cancel the mobile plan.

Ang marks the focus/topic of the sentence.

In English, learners often expect ang to always mark the subject, but in Filipino that is not always the best way to think about it. In this sentence, the verb is object-focused, so the thing being canceled is marked by ang:

• Kanselahin ang mobile plan
• The focused thing is ang mobile plan

So ang mobile plan is the item receiving the action.

Because in real-life Filipino, many modern business and tech terms are commonly left in English.

Words like these are often borrowed directly:

• mobile plan
• customer service
• billing
• account
• refund

So this sentence sounds natural in the kind of Filipino used in customer support, telecom, or office contexts.

Here, sa customer service means something like:

• through customer service
• with customer service
• at the customer service department

The preposition sa is very flexible in Filipino. It can mean to, at, in, on, or sometimes something close to with/through, depending on context.

So in this sentence, it does not just mean physical location. It can also mean the department you should contact to do the cancellation.

It is best understood here as a department or service channel.

A native speaker would usually understand it as:

• the customer service department
• the customer support line
• the place or team you contact for help

So sa customer service can refer to either:

• a physical service desk, or
• the support team in general

The exact meaning depends on the situation.

Yes, it is understandable and fairly natural, especially in a business or telecom context.

That said, many speakers might also say:

• I-cancel ang mobile plan sa customer service.
• Ipakansela ang mobile plan sa customer service.
• Kanselahin ang mobile plan sa customer service department.

So your original sentence is fine, but in everyday speech Filipinos often mix even more English into this kind of sentence.

Yes. In everyday spoken Filipino, i-cancel is very common.

Compare:

• Kanselahin ang mobile plan.
  More standard Filipino structure.

• I-cancel ang mobile plan.
  Very common in casual modern speech.

Both are understandable. Kanselahin sounds a bit more traditionally Filipino, while i-cancel sounds more conversational and mixed.

It is not stated. Filipino often leaves out the doer when it is obvious, unknown, or not important.

So Kanselahin ang mobile plan sa customer service just gives the instruction. It does not explicitly say:

• you should cancel it
• someone else should cancel it
• I will cancel it

If you want to include the doer, you could say:

• Kanselahin mo ang mobile plan. = You cancel the mobile plan.
• Kanselahin natin ang mobile plan. = Let’s cancel the mobile plan.

A plain imperative can sound direct. To make it more polite, you can add a polite marker such as paki-.

For example:

• Pakikansela ang mobile plan sa customer service.
• Paki-cancel ang mobile plan sa customer service.

These sound more like:

• Please cancel the mobile plan through customer service.

This is useful when making requests rather than giving instructions.