That makes me think that he had your letter for that long and then decided to RTS you.....it would have taken almost the same amount of time to sign your cards and send them back after almost 3 years!!
No he probably sent it back right away...its the p.o. who had it that long it most likely found its way to the lost&found
facility in Atlanta GA..since it had an address and postage they decided just to mail it.