FED UP AND FRUSTRATED CLIENT!!

So fed up with the service i am receiving from these guys. i had TT connect replace my router box yesterday, and ever since my wifi is useless. I have called them 4 times in the last 12 hours still no one has been able to phone me back or to resolve the issue with the connection problem. i keep losing connection, i cannot operate my business from home due to this. They are quick to react when one has an unpaid payment, but when one has connection issues they are no help at all. Resolve this or remove the new box that was installed as it is no use to me. i cant see what i am currently paying for!!!!!!