The last time I had a redeposit issue, customer service told me reservations was supposed to handle it. Reservations had transferred me to customer service. Customer service said many phone agents incorrectly believe that because CS has aadvantage in their name CS is supposed to handle award miles issues. Reservations had done the initial processing, but the miles hadn't reappeared. CS did finally agree to push through the redeposit. I have no idea whether anything reservations or CS told me is true.
Good luck!