(correction please) It’s really annoying when people use mobile phones on public transport

I partly agree with this statement it. I think that when you are for example on a bus it’s really annoying when someone is shouting while is talking with the on a mobile phone. I also think that they (these people) are antisocial as people they are too busy sending messages to talk to the people in front of them. But on the other hand, they (mobile phones) shouldn’t be banned because they can be useful in case of emergencies and can be used to help us, for example with maps. Mobile phones should be banned in places where they interfere with equipment, interrupt a service or break rules, such as in a library, but on public transport they should be allowed as long as they are used in a way that with is respectful to others.

I would write the noun (i.e. what I put in the brackets in yellow) instead of 'they'. You can just use the pronoun when it's clear what you're referring to, but it is a bit vague the way you wrote it, although grammatically correct.