Unable to Change TikTok Username Due to Policy Violation

I recently tried to change my username on TikTok, but I received a notification saying it’s restricted due to a "policy violation." I’m genuinely confused and would like to know the exact reason for this restriction. As a seller specializing in collectible knives and prayer beads, I’ve seen countless other accounts selling similar items without issue. I don’t understand why my account is flagged for something I wasn’t even aware was a violation. I need clarification on what rule I supposedly broke, and I’m requesting a resolution to this problem. Please address this issue promptly, as it’s affecting my ability to manage my account effectively.