no access to my control unit!!

Hello, I drive a Golf 4 V5 with 110 KW bj. 2000 and wanted to read out my control unit, as well as activate comfort functions! But no VW workshop manages to read out my control unit! it always stands “locked” then they wanted to re-play the control unit software because they thought that my software would be defective! —does not play! “locked” now wanted to sell me a new control unit! but why? my car runs like one! (with a few small m) acken :-)) Bosch has also not been able to read out their own control unit :-/ do they want to fuck with me? has vw had a lock installed on some models?