No internet connectivity issue with RSAWeb fiber

Hi I am using fiber internet connection from RSAWeb. I am facing no connectivity issue every week for last 2 month. Every week I have to raise ticket and have to call them to get the update. After spending so many time and money they some how fix the issue and very next week issue started again. I have requested so many time to come and check the issue but they are just rejecting my request. I have decided to cancel their service but RSAWeb told me that I am in contract and have to give R850+ as cancellation charge. Also asked many time to give me manager email id or contact so that I can escalate. But they are avoiding my request. Every month I am paying money for this service. I am seeking help please.