Cannot Opt Out of Credit Offer

I received a Truworths card, vouchers and line of credit from Truworths in my postbox. I never requested this nor have any desire too. I called the number on the (exclusive) Offer letter *** to opt-out. However there is no easy way to opt out, they insisted on having my ID number which I refused to provided and seem to have no ability to tie the Offer Letter Reference Number which is also the Account Number in order to satisfy my request, nor could they funish any details on how my information was obtained. A supervisor wanted to transfer me to the marketing dept to research this. If I read the Credit Act and Finance Institute laws correctly you have to provide the ability to Opt Out of said offers and identify how and when the (potential)customer details were obtained. My challenge to the Inept Truworths is to ensure that you comply with regulations.