if anyone one is calliing you and you have asked them to stopp calling you by phone,ans uyou have stated you will and wish only to be contacted by letter,after that popint it could be harrasemnt via telephone,this can be brought to the attention of OFCOM and OFTEL who licence these call centres and take a dim view with fines for breaking there guidlines,trading standards and the office of fair trading would be intrested to and you should mention all off the above in your letters sending them recoded delivery,you may want to take legal advise and state this in your letter also,maybe a letter from your lawyer to this creditor legal department would do the trick stateing there calls are causing you distress and to only contact his client by letter in future,your first interview with a lawyer is free,a letter costs around £40 i think,but check lawyers charges,maybe money well spent....been there done that,,,if you have unsecured dept over £15k think about a DAS,not a DMP,,contact your local CAB for advise...asap!!!