Advice needed! Disabled traveller, hotel did not provide facilities despite requesting

Hi I was wondering if anyone can advise me on my next step?

My two friends and I went to Dublin at the beginning of June to see Michael Bubl!!. We booked the tickets, flight and hotel in November. We booked the hotel via booking.com and as I am a wheelchair user I take a great deal of time making sure the hotel has disabled access and facilities. The hotel had that and I wrote a request for walk in shower whilst booking.

When we arrived at hotel at 11.30am on day of concert we were told that our room was ready but it didn’t have a walk in shower but if we were prepared to wait until 3pm we could have a room with one. We agreed to wait. We returned after 3 and checked in. The room they allocated was a room with a double bed a single bed plonked in the middle of the room and the bathroom had a bath with shower over it. It did have grab rails. It would have been difficult for me to use this and move around room in my chair. We went back to reception and were informed that they did have walk in shower rooms but were occupied but we could have the room tomorrow. We refused. The only other room they had was a suite. We looked at this room. Granted it was bigger and they said they would provide a stool for me to sit on to have a shower. We had to accept this as by now it was about 5 with all waiting around etc and needed to go to concert. We were assured that all items towels etc would be provided for three guests. These never materialised despite repeatedly asked for.

To cut a long story short we spoke to manager on leaving (couldn’t speak to him beforehand) and he said it was hotel’s fault and for inconvenience he would offer fifty percent off a future booking within the chain (nothing in writing) and we (him and us to arrange a 50% refund) would get in touch with booking.com on our return. We have contacted booking.com and after two weeks hotel has refused a refund but because of inconvenience and time it’s taken booking.com offered a €90 refund. We were wondering if we could carry on complaint? Sorry for long post. Thanks in advance