no connection still

I wrote a complaint on this site in October 2018 after having lodged problems with their call centre numerous times and still have no or almost no connection. I have subsequently been to the Buccleuch centre to get help but still I often don't have connection. It has been requested that they check the error codes when the connection drops but still nothing. Today I have had no connection for most of the day. I have had the handset checked and a SIM swop - futile. 084 153 doesn't connect from a landline so I am stuck. The technical department say that someone has been to my house to check but I live in a secure complex and no one has been - it is a lie! I want to cancel my contract as I am not getting the service that I pay monthly for.