Dissatisfied about Rain Isp

I am struggling with connections speed . Youtube keeps buffering. Mostly speed test between 1 and 2mbps worse in the evenings .so I cannot recommend Rain network coz of poor speed. You cannot finish a meeting without getting disconnected. I am actually planning to go to another service provider. When I put a vodacom sim card on the same device I get 9mbps so what's the actual problem here