Discovery will not give the client his money back

An update on the last post, after 20 minutes of being on hold, Discovery admit they took a debit order from a client which they should not. They will only refund the money to the client if I as the broker agree, that if the client returns the debit, that I as the broker will be liable to refund Discovery. Without this they will not refund the client for 40 days even though they are 100% at fault. They are only interested in their systems not the fact that a clients debit orders with other people will be returned because of their mistake.