Billing Issue for over a year.

I am having the worst billing issue that has dragged on for over 12 months. Supersonic continuously accuses me for not paying for 2 months... i send them the proof of payment from my banker, they are still not satisfied!! Every 3 months we keep having the same conversation! I send proof of payment, I am sure they want my kidney's now while they keep disconnecting my internet and lose work for over 2 hours. Please if you think internet is worse their billing finance is thee most painful to deal with, the service for me has been painful. No ways.