please help..!

[hustler]

Hi,
I have a retail business selling domestic appliances. I sent a washing machine to a customer via a courier but it never arrived. The couriers admitted responsibility eventually and I therefore had to refund the buyer. The buyer was very abusive and aggressive so I (foolishly) didn't give it top priority and ignored his letter.
Eventually a letter came from the court asking for the refund plus the court costs.
I posted a cheque straight away for the full amount paid plus the £80 court fee (totalling £753.00) so I thought that would be the end of it.
But now the buyer has sent the cheque back with an official letter from the court, so I am confused what exactly he is trying to do.
On the original court form he states that the claim will be for no more than £1000.00.
I am concerned that he will be asking for court costs etc, any ideas?

Thanks in advance