Internet not working

[Internet1]

Can someone explain what is going one with my internet????????? 
I have called O2 many times and make complaints about my internet. This is getting ridiculous now and I’m going to cancel my contract. 
I’ve got full signal and the internet still not working. 

[gmarkj]

Have you checked your APN settings are correct @Internet1 ?
Is your phone trying to connect to WiFi or are you talking about mobile data?

See if these guides help:

Guide: How can I sort out my network issues? 

Guide: Is the network down for me or everyone? 

[Bambino]

@Internet1 O2 doesn't guarantee 100% uptime. No network does. See if anything in the guides provided by @gmarkj help.

If you cancel your contract you will have to pay any months still remaining: Cancelling your contract - An updated guide - O2 Community