No internet since 18 April

Shocking..I would not even recommend this service to my worst enemy. Firstly the internet is slow, 2ndly they just disconnected my sim since Sunday been calling and emailing literally everyday but no help today is the forth day i'm sitting in my house with no internet yet i work from home. Spoke to another agent yesterday who said that he will arrange for a sim swop, till now I haven's heard anything from them. I keep getting auto replies with subject DEREGISTERED (I wonder what it means). I would rate them zero at this point.