incompetance describes archers to a tee!!!

Last year we booked a River Cruise and being the first was looking forward to it. We arrived only to find out when we were on the boat out cabins had been downgraded to the lower deck. Despite pleas and ringing the UK we could not get it resolved and so it was a great start to the holiday at the rear of the ship with engines vibrating. Our friends who had been on a boat with Archers before said this food was well below standard with dishes like rabbit being served up.
We booked this year as we had a voucher as "compensation" and all seemed well until today when we got an e mail saying due to an error our top deck cabin was not available and we were being downgraded to the lower level.
How can this happen 2 years in a row? either they are becoming like airlines and over booking or its mass incompetence on behalf of the staff.
I have written to them and have met a wall of silence. I will never recommend Archers again they are a complete and utter incompetent shower who treat customers like dirt. I have never written a bad review before but they deserved this one