Trying to Purchase complaint

I have tried to contact a “real” service rep to no avail…I am an avid lover of all Diablo games…Playing since the advent of Diablo 1…I presently playing Diablo 4 Season 4 Level 95 Barb… Try as I might to prepurchase a copy Vessel of Hatred I am stopped at the final payment screen asking for my password which it refused to accept- yet my password works fine when I access the game…Do I have to create a NEW password to access purchasing a new game? And if so, will I have to create a NEW password to continue playing the game?..Thanks for any advice.