Slow speeds during peak hours tech says exchange is the problem

We recently got fibre in our town after years, and at first, the speeds were true to the package. I'm on the 50/25 Mbps package, but after a lot of people got it, it seems the exchange can't handle it, and during peak hours, we don't even get 5 Mbps. OpenServe keeps saying there's a problem with the exchange and has no idea how long it can take to be fixed. This is really disappointing, as I'm paying R700 a month. We were promised that this was better than ADSL. What more can i do, i phoned telkom countless of times and they say they cant do much because the problem is with openserve