I'm mad and hurt. Rightfully?? I was accused of forgetting a birthday I didn't forget and then snubbed on mine?

I called my Dad on his birthday 2010 and was promptly dismissed with 'I really am not in the mood to talk'. Which I respected, however I was able to say happy birthday and I love you before I hung up. I'm not at all wrapped up expecting huge plans or gifts for my birthday. nor do I get sad about my age. But imagine my surprise when the whole day of my birthday ped without even a phone call from either parent and I'm an only child so I doubted they forgot. The next day I called as usual, we talk everyday, and I said I was surprised not to have heard from you all for my birthday. Well, my mother said well you forgot your fathers birthday last year and that was so inconsiderate that we just decided to never mind yours! I reminded her that my father hadn't wanted to talk and didn't want to do anything and she did recall that but didn't say sorry for the accusation. It really hurt my feelings that they actually sat and plotted to 'get me back' for something I didn't do. If they'd forgotten I'd easily get over that. I can't imagine setting out to be that spiteful. Well, this year I called again and I got the 'I'm too busy' excuse. I said to them both--well, just you remember that I called. No nonsense about not recalling these birthday wishes, ok? Is that fair enough or should I have done something else?