MTN Wifi in Pretoria

This is now the 2nd time this year that I have problems with my wifi. Everyday when I leave home I switch it off. Switch it on again when I return home in the afternoon. Since Thursday the week before last, the trouble started again. It is working perfectly then the red or green light will come on so "connected without internet". This can go on for hours. If I wake up during the night all the lights might or might not be blue again. Sometimes, after switching it off and switch on again I have internet for a few minutes before everything starts over again. I have with the previous some problem, called MTN. The people are always friendly and professional but the problem starts a few minutes uses after I put down the phone al***** again! Some assistents at MTN shops tell me it is our tower and reception. Then suddenly everything is working again for the next 3 months. The problems start again . I'm really tired to fund my wifi from payments to keep my phone online. Although I am paying for my wifi, I have to ad (paying) moble data constantly, costing a fortune.