P and O Cutting back on service

Went to book a couple of days at the Retreat as soon as we boarded only to be told by a very brusque woman at the Spa that it was fully booked for the whole cruise. The same with the Limelight Club for the first act only to find that on the first night there were only about five people in there. We normally go with freedom dining and have had very little problem booking on the app on our last cruise on Aurora but the second night (black tie night) we waited 90 mins for a table as did many others and only managed to eat at 9.30pm as we agreed to share a table , but when we got in the restaurant we found there were many empty tables. We then changed to club dining for the remainder of the cruise and had brilliant service. We did complain in our on board survey and were given a bottle of wine at dinner but it still spoilt the cruise for us. Struggled to book at Sindhu on the app but managed to change the time we were forced to book on going up to the restaurant.I dont know if it is the app at fault but we would never go on Britannia again. Our steward and all the waiters in the restaurants were brilliant but service was not good in the bars. My husband ordered a Prince Charles coffee in the Crows Nest only to be told there was no Drambuie or Cointreau on board.
After having many cruises with P and O we are now considering other cruise lines.Such a shame.