Ex doesn't send DS back with his stuff!

[mosa9]

DS has been staying there about 2 nights a week.
I haven't checked when he's been sent back with his clothes until we're home and I haven't remembered what I've sent out (but I usually send him with 2 clean outfits & pyjamas).

I've had to buy 2-3 outfits and socks in the past few weeks because we keep running low.
DM bought him a couple of pairs of pants too over the weekend.
Got up this morning to do washing expecting to at least have 3/4 of his stuff in his basket and I have about 3 outfits in total in there, missing a new pair of pyjamas and most of his pairs of socks.

AIBU to be really angry about this this morning?? I don't buy stuff for him to stash out there.
I got a few outfits back at one point by not sending him out there with anything (there was a fuss every time he wasn't sent with anything) but I'd explained that I wasn't getting enough stuff back to do that and that I wanted his clothes back!
The couple of occasions I have checked the bag before we left and asked why it's empty, I'm told the stuff is already in the washing machine.

Been there OP. Early on I told him he'd have to buy clothes himself, but he'll always send her home now in too small underwear and keep the stuff she went in that fits. He also refuses to pay anything. I sometimes wonder if it's just that he's disorganised or whether he's doing it to get at me, but DD is starting to realise now, so I'm hoping we'll get to end of it soon.

We’ve got the other side, DSC turn up in school uniform and school shoes, are sent home in clothes and shoes we’ve bought never to be seen again.
Same with undies / socks etc. We buy nice packs of undies and they go home in them only to turn up next week in knickers 3 years too small.
We have everything they need here but it was costing a fortune to send them home in clothes then having to replace them when they showed up in uniform again the following week.
Nothing has ever been returned, DP now refuses to let them in the car unless they are in normal clothes and they get changed before he takes them home the following day, it feels extremely petty to have to do that but Ex has admitted to throwing away items we’ve bought so unfortunately until she grows up we have to be super petty. Depressing.