Originally Posted by Often1

Before you call anybody, make sure that there are no other changes which could have caused all of this.

Needless to say, the returned payment would trigger a credit review for obious reasons and even a temporary suspension until you made good on the returned payment.

But, it's unlikely that the returned payment alone would have led to the result. Have you had other credit problems, is your business in good shape, is it out of compliance in any way?

Once you've eliminated everything else, then go ahead and make your calls.