[2021] 10 hour Matchmaking Lock!!??

If you wish to appeal your DC Penalty, you can do so here: https://support.deadbydaylight.com/hc/en-us/requests/new?ticket_form_id=360000836752 If you believe it's a bug and not because of previous DCs. The DC penalty starts low to account in for emergency situations, so unless you disconnected a lot before, it should not be that high instantly.

Considering depending on what you mean with "you did in the past."