Moving contact

Hello, I moved to a new apartment and want to move my dsl-connection here, the moving-form said that my current tariff L is not available here, online check for available tariffs suggest that I can have maximum 50 mbps here. I called hotline and a very rude lady said that the only solution is change my current tariff to M, but it will extend my contact for 2 years and that's not acceptable. At my current contract address I also have only 50 mbps, so please, move my contract to a new address without changing tariff