extremely poor service

I booked a holiday with On The Beach for my son and I, destination Orlando Florida.
My son has Autism, a severe communication disability and a learning disability.
I specifically booked my holiday with a self catering apartment as my son has dietary needs. I also booked a hotel with slides as my son gets great pleasure from these.
Upon arriving to the hotel, the room we had was just a room with no facilities for cooking. I asked the hotel if I could be moved to a room with self catering facilities only to be told that none of their rooms are self catering.
I contacted on the beach which took at least an hour to get through and had to wait the whole day for their response which they offered £200 compensation and told me there was nowhere else we could stay? I was of course extremely unhappy about this. I advised them that this was their fault due to false advertising and it wasn’t good enough. My son needed to eat and relax as he was immensely stressed and unsettled due to all this.
I then had to wait another day, of which my son didn’t want to leave the hotel room due to stress and eventually on the beach came back and told me they could only offer another hotel which had self catering but no slides approximately a 30 minute drive away. I again expressed my dissatisfaction about this as i specifically booked a hotel with slides for my son's enjoyment. They had no other option for me so I was forced to accept as my son was inconsolable at this time and needed to know what was happening.
I had to pay and arrange my own taxi to the new hotel and I also asked about the transfer to the airport from the new hotel which I was told it had been all arranged and I even received a confirmation email stating that the taxi company was to transport back to the airport from the new hotel.
My son struggled to cope on holiday as we had no slides so I had to spend a lot more money to keep him occupied.
The final straw was phoning the taxi company 24 hours before departure only to be told that the company does not pick up from that hotel, I therefore had to pay for a taxi to the airport.
I contacted on the beach when I arrived home with a formal complaint, it took 29 days for their response.
All they could say is that they were sorry and that the hotel advert was a computer error which was now rectified.
I am now in the process of pursuing this.
Please do NOT book with On The Beach