Strange experience with a BA booking

Backbiter

We have booked a cruise for next September that leaves from Venice and ends in Barcelona. We then booked two one-way flights with BA, to Venice and returning from Barcelona. This was in early October. We part-paid using Avios.
The other day, while paying our credit card bill online, I noticed a refund from BA listed under recent transaction (our latest bill is not due for another week ) . Not knowing what this was for, I went into my BA account, and when I entered the booking ref for the Barcelona flight, it said 'there are no flights for this booking'. I searched my email inbox but found no message from BA explaining the cancellation.
I rang them but the agent I spoke to just said our booking had been cancelled and that we had been refunded. He could not explain why. The flight itself had not been removed from their schedules. I told him we needed the booking to be reinstated as it was part of our cruise holiday. He said we would need to 'go to the airport in person' to do this - I couldn't do this on their website!
I also pointed out that we had not had our Avios returned to my account. I was told to lodge a complaint with the airline, which I have now done.
They have subsequently returned my missing Avios, and I have now rebooked us on the exact same flight. However, in the weeks between me making the original booking, the flights have increased in price. Not only that, but - as BA charged my credit card in Euros for the Barcelona-Heathrow flight - I actually lost out on the refund, and received less than I paid due to currency transaction rates and charges.
All told I am about £40 out of pocket, and am utterly mystified at what has gone on. It is possible that I might not have discovered this cancellation until just before check-in next September, as BA have failed to inform me in writing. Their agents have provided no explanation. I trust that in dealing with my complaint they will ensure I am not left out of pocket. And any goodwill gesture to compensate me for the time spent sorting this out would be very welcome.

Backbiter

Well, fair play to BA. Just had this email:

We’re very sorry to hear about your recent experience with British Airways. This isn’t what you should expect of us, and we understand why you needed to complain.

Thank you for letting us know - please rest assured that your feedback has made a difference. Your comments have been shared with the relevant team and we’ll be using them to help us to improve our service. We’d also like to thank you for your patience while we got back to you.

We’ve added 15,000 Avios to your Executive Club account and we hope this goes some way towards making up for your experience. You can exchange Avios for flights, upgrades, hotels or car hire – please see ba.com/avios for more information.

Once again, please accept our apologies. We hope to welcome you on board soon.

No idea why they should have randomly cancelled my booking, and they have offered no explanation, but I am happy with their resolution of my complaint.