Shocking service Cell C

I have a technical issues with my fibre at home. I am told they cannot solve it as they are just the middle man to Vumatel. Vumatel tells me it is Cell Cs problem to solve. I have now cancelled the contract. I have also now have a credit on the account which I am unable to arrange for the refund as the answers I gave to the security questions are apparently wrong, which I can confirm is not the case. Absolute shocking service. Been on the telephone for more than 3 hours without success.