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You do not have a "right" to an Amazon seller account. They can shut down your account for any reason or no reason.
You do have some remedies as to the money in the account. You could file a small claims to recover them money they are holding. However, your user agreement probably has some language about this issue, and a forum selection clause.
So your best bet is to see what they do after the 90 days, and check your user agreement for remedies if you want to sue for the money.
You can't force them to let you sell, but they cannot keep your money