Downgrade of ADSL line for no reason and not informed

I recently signed up for the unlimited wifi special that Telkom had on a 4mg line. About 3 months ago, I started receiving buffering while watching Netflix but I did not think anything of it. The buffering became progressively worse to a point where I could only watch 2 minutes of a movie and then it would start buffering again. Also, my landline has a constant crackling tone and one cannot have a decent conversation on the phone. When I contacted Telkom, I was told, to my surprise, that I have been downgraded to a 2.5mg line - how on earth does this happen without been given prior notice or providing valid reasons for the downgrade? The technician then upgraded my line back to a 4mg line and he promised a follow up call to check if everything was working properly again which I am still waiting for. Bear in mind, my husband and I have an 8 to 5 job hence we hardly stream movies nor use the wifi often. My question is, is Telkom going to credit me for the months that they have downgraded me??? This is definitely not what I signed up for. It is also impossible to even try and get through to the 10210 number. The service from Telkom is absolutely pathetic and appalling.