Really hard one, especially with the £400 door in the frame. (pun not intended!)
I think though that behind the agnger is often a slightly frightened kid who doesn't quite know what to do with life, and is making a pile of crap choices. You need to keep the door open to that kid.
Mine is 16, and I am amazed at the things he thinks, so when I am grumpy that he is late in the morning, he genuinely thinks I hate him for being late.
I think expressing love to teenagers is unbelievably hard. I also think they can hate being the focus of attention too. But I do think it is veyr important.
So, I would write a card. Tell him that you know things have not been easy between you for the last few months, but that he needs to know that you love him, and that your door is always open. Tell him you are sorry that there isn;t much money due to the door, but that you do want to celebrate his birthday.
Buy him something small, that he will like. Have a cake and his favourite meal. Let him know that you are doing that, otherwise he may just go and hang out with mates and not come home.
This isn't rewarding his shitty behaviour, it is reminding him that he is loved, which is so important as a teen.
he will revert to shitty behaviour asap, the goal is not to stop it, the goal is to remind him he is loved, so that when he is ready to change, he knows that you are there.
Oh, and stop worrying about food etc, pick your battles.