terrible billing and service issues

I took out a contract in January 16. They have loaded the incorrect contract on my name. They started to bill me incorrectly. Now they deduced alot of money but its been 3 weeks since a case was opened but no response. All of a sudden 3 days ago my cell loses signal and now I cant even use my phone. No one can tell me what the issue is. I tried som swap but was sent to the branch then to the call centre then to the branch and then call centre again. There is an error on the system and they now can't do a sim swap. So now I have been charged for the contract but still I can't even send a free sms or make any calls. What ******* is this. I cannot get a direct line to a manager or to their stupid back office. The back office is the issue but they are loke government, you don't hear from them and they cannot be touched.