Purchased extra legroom seats. Got to checkin "Those seats have been allocated to someone else" No explanation why. We were then given seats in row 25, the worst seats on that particular aircraft.
Boarded aircraft, spoke to aircrew "Aircraft changed from A320 to A319 - seat configuration different, complain to BA". There were empty seats in the forward part of the aircraft and we were the last to board. We asked if we could sit there. "No, if we let you sit there everybody would want to sit there as well".
My son-in-law who booked the seats put in a claim to BA who responded "No record of changed aircraft and no evidence that you did not get the seats you paid for." He has followed this up with their customer services and awaits a response.
I had a similar occurrence with Thomson Airways, and a refund was given straight away.
We travelled from Verona to Gatwick 13 June 2018. Our outward bound flight on 6 June 2018, BA2598 was delayed, so the cabin crew brought round water and biscuits. One passenger asked what flavours there were of the biscuits. The response from the female flight attendant was "You get what you are given". That just about sums up the attitude of BA.
There is no way I will ever travel with BA again their customer service is beyond belief.2