No Connection on 4G when it has good 4G coverage

[RMM]

I have not had a data connection in my local town (Haddington, EH41 3DX) for over a year now. I have done everything asked of me. Network setting reset, replaced SIM with a new one. I have even purchased a new phone yet the same issue arises. It used to work for years so there is coverage. I can make calls no problem.  It shows almost full bars on 4G coverage but will not ever let me browse the web, download a text email or even use Facetime. I have searched social media for the area and no one else is having an issue. I live 5 minute away and it works fine there so presume that is different mast. I have recently tried again to get an answer from O2 and they said "Our Network can get busy in this area." and that was all. If this was the case I would surely be able to occasionally get on especially late at night and if not there would be thousands of people complaining about this and on social media? Doesn't make sense. any suggestions as hugely frustrating. 

[MI5]

@RMM 

You need to ask customer service to escalate this to the network team for investigation.

Insist and don't let them fob you off.