Time To Process A Cheque

I am appalled at the time the Nationwide takes to process a cheque.  I put a US dollar cheque drawn at a major global bank into my account at the Nationwide branch in Chesham on the 26th of November 2011.  The fee is around £20.00, and I signed the form and handed over my cheque.  More than eight weeks  and four visits to the branch later they still have not credited the cheque to my account, nor will they find out where the blockage in the system is so I can cancel the cheque and go elsewhere.  Other people have had these cheques processed by Lloyds TSB and HSBC in about one week and with only a £10 fee.  I sit in the branch for hours, they tell me the person that deals with CHAPS isn't in, I ask to speak to the manager, they tell me s/he isn't in, and they promise to call me but never, ever do.  I ask if they have a formal complaints procedure and a form I can fill in - they do, but they don't give me the form and tell me that "the manager is aware, it has already been escalated".  After insisting over and over again, I finally get an address (no phone number) for the Head Office.  Now well into 9th week and still no sign of my money!  Absolutely disgusted!