Help Needed - Negotiating Flight Cancellation with British Airways

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Check whether the ticket can be transferred to a different date for a fee, often this will be the case on non-refundable tickets.

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As others have said, as the tickets state they are restricted / non-refundable then you won't be able to get your money back from BA.  These are the T&C's agreed to when booking the tickets. You'll need to claim through Travel Insurance assuming the reason for cancellation is covered by the policy.