If one party didn't pass the interest in the property to the other when you split up, then you are both liable for any shortfall.(posted 8605 days ago)You would be best dealing with this as a united front. I do know of an case where the lender received a small amount in "full and final settlement" from one party, and then went on to chase the other party for the full amount - neither of the victims knew what was going on.
Lucy you should write to the lender and ask them to refrain from sending letters to your place of work. Ask them to send all correspondence concerning the shortfall to either your address or your ex-partners.
Pendle