Santander loan came back 1 year later?

ryeates

Hi my wife had a loan with Santander,she was left some money so she did the right thing and paid off any debts before spending. She went in to the local Abbey branch and asked for the settlement figure and paid off the loan there and then £1973.36.
about 6 months later she had a letter from them saying that she owed then money so she called the up and explained that the loan was fully repaid and they apologised and said it was an admin error.
Last month almost 1 year later £1973.36 appeared as a credit in her bank account she left it there as she had no idea where this money came from. Today a letter arrived from Santander saying that they were requesting payment of an outstanding instalment and they had refunded the money back into here account. She called them and they said that if she paid them a cheque for the money they refunded then this would be full and final settlement.
What I don't understand is they gave her a final settlement figure 1 year ago which she paid they have now refunded the money 1 year later and tried to start a new loan which she does not want or need was common sense made redundant during the banking crisis or are the really that desperate for new business?