I had the same propblem a few days ago. I had two car tickets that I could not get the game to accept. So I sent a bunch of paint chips from a secondary account to the account with the stuck gifts and when I went to accept them I clicked on the "Receive All" button. Next thing I know the 2 stuck car tickets were accepted (along with the paint chips). :-)
If you don't have a secondary account to send stuff from send me a FR (same as my forum user name) and I will send you a bunch of paint chips. Just let me know if there are any colors in perticular that you would like.