Bad service from Cell C

We have been a customer of Cell C for more than 10 years and we never had so much problems with them than this past year after upgrading our Cellphones and wifi it seems like it don't want to connect to the internet. What is the use for paying a lot of money for services that we can't even use. When we call them for advise they say it's a signal tower fault but they working on it we getting the same answer now for more than 6 months.