CeX sold vulnerable son a damaged game that cannot be returned

My teenage adult son has had an immensely difficult few months and while we are out of crisis mode (where I literally had to be with him full time due to risk of going onto SSRIs) its clear that he is quite vulnerable (how he interacts, wearing a mask, hides his face behind his v long hair. )
Today we went to shops he likes in dublin city centre. He made a purchase of a skylander game in CeX Georges Street (he normally shops in a different Cex), as I looked around.
They basically sold him the disc only, which should have been part of a starter pack but they didn't have the other pieces. They charged him the price for the starter pack and said to him that if he bought it , that he would not be able to return it as they had to put it through as the starter pack.
He has just come into me, very upset that the game isn't working, and that he had expected Cex to have checked it out before selling it.. and how he couldn't return it.
I absolutely don't care about the cost but I'm furious about this, that they sold a useless game that is part of a pack, that could not be returned. It's just totally thrown him off, as he is so careful with his own games and disks, and was so excited to purchase this as it's difficult to get..
I had no plans to go into the city centre but I can try get in over next few days . But what should I say?? The receipt is going to say the full starter pack but I'm not going to have the full pack as they only sold him the disk. Should I email or phone first ? I cannot prove that they sold only the disk.
Genuinely livid here so any advice appreciated.
Separately I'm going to scour other Cex stores to see if I can get the game pack for him.. Skylander spyros adventure for Wii.. or if anyone knows of other stores that may be able to source this please advise.
Honestly, this has just upset him so much.. It's really hard to explain .

Sorry to hear about your son having a tough time. My gut feeling is that there are 2 issues his low mood and the skylanders disc seems to be the final straw in something that may not have caused as much stress ordinarily. I think maybe a phone call people can be surprisingly understanding at times and the fact that CeX do take second hand products I would try and have a conversation with a manager.

I would not put any extra energy into this situation other than to see if then will take it back maybe even a store credit then maybe try and source whatever he is looking for from anew. I think communication is the key in these situations and often with the right approach retailers can be reasonable and open to compromise. That said there are always some that will not help and if that is the case I would probably just manage the situation and maybe even tell my child I had gotten the money back albeit not the truth.

Good luck with finding a resolution hopefully you can sort something and direct your sons attention to the enjoyment of finding the game he is looking for with all the parts.

There shouldn't really be an issue here. I expect that CeX will readily refund your son when asked and may well locate the missing pieces for him if you or he asks nicely.

Try order it online maybe, can be returned under distance selling

Link to what looks like a full set here: