Just found this template letter on money saving expert. Make sure you send it recorded. If they continue to call you, tell them you'll go to the police for harrassment. Hope this helps
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Company Name
Road
Town
City / County
Postcode
FORMAL COMPLAINT - HARASSMENT BY TELEPHONE.
Account Number:XXXXXX
Dear Sirs,
I am writing in relation to the quantity and frequency of telephone calls that I have received from your company, which I deem to be personally harassing.
I have verbally requested that these stop, but I am still receiving calls.*(Delete if necessary)*
I now require all further correspondence from your company to be made in writing only.
I am of the view that your continued harassment of me by telephone puts you in breach of The Consumer Protection from Unfair Trading Regulations 2008, and the Protection from Harassment Act 1997.
If you continue to harass me by telephone, you will also be in breach of the Communications Act (2003) s.127 and I will report you to OFCOM, Trading Standards and The Office of Fair Trading, meaning that you will be liable to a substantial fine.
Please treat this also as a formal complaint under the procedures set out by the Financial Ombudsman (FOS). As such, you are required to send me a copy of your company complaints procedure.
Furthermore, please note that the FOS consider it 'unfair' for you to continue with phone calls when requested not to do so.
Also the OFT consider it an unfair practice for you to ignore my legitimate wishes on how to contact me, for example where the debtor requests contact only via written letter or email, so I now demand that you cease any phone calls forthwith.
Be advised that any further telephone calls from your company will be recorded.
This issue is not negotiable. Any further phone calls will be logged, treated as harassment and reported to the authorities as such.
Yours faithfully,
(type don't sign)