British Airways (BA) has warned that customers calling to re-book affected flights may struggle to get through to its call centres.

The airline’s issues have been compounded after a number of passengers received emails on Friday mistakenly telling them their flights were cancelled – only to find out later that it wasn’t the case.

BALPA says that during several days of talks it put forward a number of packages it believes would have resolved this dispute without a strike, but BA didn’t accept any of the offers. It says 93 per cent of its members voted in favour of taking industrial action.

BA said it proposed an offer of 11.5 per cent over three years to BALPA, a deal which the airline believes “is fair”.

BA is now making changes to its schedule. But it has warned that passengers with a flight booked with it on the strike dates will be unlikely to travel. All affected customers will be offered a full refund  or the option to re-book to another date. However, passengers are only eligible for compensation if they have been given fewer than 14 days’ notice before the flight.

BALPA says a day of strike action will cost BA around £40m so three days will cost about £120m.

The union said that in recent years BA pilots have made “sacrifice after sacrifice” to assist the company such as taking a pay cut, productivity increases, closing the final salary pension scheme, giving up annual leave days, a new rostering system, and reducing flying pay.

Adam French, consumer rights expert at Which?, said: “It is unacceptable if frustrated passengers are unable to get through to customer services at British Airways. If people can’t find out what their cancelled flight means they could be deeply concerned that their travel plans will lie in tatters.

“If you are affected it’s important not to panic, BA has a legal duty to reroute you onto another available flight – if necessary with a rival airline – so keep chasing the airline and find out your options. Anyone who has already booked themselves onto an alternative flight can seek to claim the cost of the original flight back but will need to enquire about this with BA.”

A Which? survey found BA is the airline most likely to leave customers disappointed when they complain about problems with delays and cancellations.