Learn Spanish (Latin America): Cuelgan la llamada cuando falla el internet. - They hang up the call when the internet fails.

Not necessarily. This sentence uses the impersonal third-person plural. Even though cuelgan translates literally to 'they hang up,' the 'they' is often unspecified. It is similar to saying 'The call gets hung up' or 'Someone hangs up the call.' You will see this structure a lot in Spanish when the person doing the action is not important or unknown.

I learned that colgar means 'to hang' (like a picture). Does it always mean 'to hang up' the phone too?

Yes! Just like in English, where people originally 'hung' the receiver on the wall, Spanish uses colgar for ending a phone call. Remember that it is an o-ue stem-changing verb in the present tense, which is why the stem changes to cuelgan here.

Why is the subject at the end in falla el internet instead of saying el internet falla?

You can say el internet falla, but Spanish has much more flexible word order than English. Placing the subject after the verb is very common in subordinate clauses (parts of the sentence that start with words like cuando, que, or donde). It sounds completely natural and often highlights the action rather than the thing doing it.

Is internet always masculine (el internet)?