Unacceptable service

We are currently paying for a 4GB uncapped internet connection, but lately it is so slow that we can barely do anything on the internet. Even though we are paying for an uncapped connection telkom is constantly switching our internet off saying that our usage is too high even though all we do is general usage such as social networking and watching videos on youtube. Any time we call to find out why we just get told that it is a problem with our modem device although we have proven time and again that our device is working perfectly fine. We never had this problem before upgrading our connection package, but before the upgrade the usage was higher as I used to sometimes work from home and our system from work uses a great deal more than facebook and youtube. I find it unacceptable that we now pay more and use less but have non-stop problems like this. Even just to get onto this website now it took more than 5 minutes for it to load, and it takes more than 2 minutes just for the search page to come up when we start up the internet.