Masterpass Account Error – "User Number Already Exists" Prevents Adding Anywhere

I’m unable to add my Masterpass account to any platform. Every time I try, I get the error message: "This user number already exists." I’ve tried removing and re-adding my cards in Masterpass, but nothing has changed. I’ve attempted to add it on Hop, Martı, and Yemeksepeti, but none of them worked. This issue is preventing me from using my account as needed. I need Masterpass to resolve this problem quickly so I can link my account without these frustrating errors.