Now that your ticket is on 016 stock, TK doesn't have control of the ticket and can't do anything about it.
Would recommend filling out the UA refunds form on their website - their refunds team might be able to action something. Calling UA is also probably more useful than calling TK - if a UA agent tells you to contact TK because it's a TK ticket, keep repeating that it's not actually a TK ticket after UA reissued it. Only UA is going to be able to do anything with the 016 ticket.