Oversold slow provider

There was an outage on 4 Oct. It took 2 weeks to fix and seems unstable to this day. Since they "fixed" the issue, my speeds are really horrible. I ran multiple speedtests and at different times at times when I need to use the internet and it looks like I am actually rate limited to 1Mbps as the results are the same each time. The 1Mbps speeds I get each time is too consistent to be a slow connection. I know peak times they manage the network and prioritise traffic, but I cannot even browse. I used to get 5-10Mbps, now I cant get above 1Mbps. ISP has told me to reset router and bla bla, but RAIN oversold their capacity and now we have to suffer.