Lack of customer support, lack of coverage, want to cancel my contract!

I’ve been back-and-forth with “customer service” (ha!) for literal months now, only to be told in my recent email I need to now use this forum, so whatever here I am…

When I took out my contract last October, everything was fine. Problems only began about January-February time where the quality of service DROPPED. Significantly. To the point I often get 0 bars of service when previously I was getting 4 or 5 bars. My mum is also on the same network (but with Three) and has the same problems as me. Can’t make or receive calls from home, sometimes not even outside.

To avoid any needless questions:

• yes, we’ve both tried using wi-fi calling; that usually gives me an additional bar, from 0 to 1 or 1 to 2, but it NEVER goes above 2 bars so it doesn’t help at all
• yes, we tried the ‘put your sim card in another phone to rule out a faulty handset’ trick
• the coverage map promises excellent service in my area both indoors & out so essentially ID aren’t keeping up with their end of the contract

...which is why I want my contract cancelled. I’ve had enough. I’ve spent way too many days stressed out of my mind trying & failing to make important phone calls (we don’t have a landline anymore) and I’m ready to say sod it and go back to my old provider!