Citibank Credit Card Complaint

Citibank Credit card department,

Advertising and marketing California

I opened a Citibank credit card account and opted out of all Citibank phone calls, checks, pre-screened offers of credit, affiliate marketing, etc. etc. on - -, -. I thought that the opt-out preferences were permanent until changed by the customer, or at least were good for 5 years. But Citibank began sending me checks in - -, not even 5 years after I had opted out. I called them immediately and them told them I have opted out but they are still sending me checks one month later. Is this a violation of the opt-out consumer protection program? Why is it SO difficult for a consumer to stop what could be described as harassment or predatory business practices?