Dishonest

<p>Was sent a letter by Mr Price stating a settlement amount on my account, showing their banking details. I then paid the amount as per the letter the very next day. I am now being harrased by a collections company saying that i owe them money. I have contacted MR Price asking for a paid up letter, to which they responded that my account has now been sold and i need to contact the collections agent. How can they do this? How can they send a letter stating settlement, receive the money and then sell the account and refuse to assist me any further?</p>