I know it is not a cheque but they are usually fast with refunds I have found. When I returned my iPad 2 before buying a new one I had to have them do a bank transfer as there was a problem in their system in store when trying to put it back onto my card and they said this was the longest option and it could take up to 5-6 weeks but it was back in my bank within around 2-3 weeks so if it has been 7 for you and they said 5-6 I would give them a ring and find out what is happening.