BA damaged baggage replaced with much worse, smaller suitcase - what to do?
I had the same thing with an expensive Samsonite Black Label case.
I basically said to BA that as this was part of a matching set of luggage, unless they could provide exactly the same case, I would prefer cash so that I could source a replacement myself.
BA had no problem giving me cash in these circumstances.
I would get BA to collect the replacement and ask them for cash instead.