I feel your pain OP. My son didn't send a card, call or text me either.
He lives in another part of the country and always comes back to our home city to see me for MD, but this year he delayed his visit by a couple of days because it's also my birthday tomorrow and he told me a few months back that he'd bought me a ticket for a show that's on tonight (that I have absolutely no interest in) as my joint MD and birthday present.
Who buys someone (especially their mum) something they know full well won't be enjoyed or even wanted? In my mind, it's totally thoughtless, like buying (normal) chocolates for a diabetic.
This is a show that he wants to see and he bought tickets for himself, his partner (who also has no interest in it) and me, so not exactly what I'd call something special for MY celebrations.
Today, he told me that as I don't want to go (even though he's known for months), he'll not be having any further contact with me, and that the voucher (that he's only just dreamt up) he was 'thinking' about giving me as part of my MD present, he won't be giving because the cost of it will cover the cost of the wasted theatre ticket, which by the way, his partner's grabby friend jumped at the chance of taking off his hands (for free) and will be going in my place.
So not only have I not even had a happy mothers day message, I'm not getting one for my birthday either. Needless to say, I'm feeling decidedly unloved and unwanted by my son this week too.