Calendar returned but I continue to receive a bill for it.

Acct # 10009118901.  I returned this calendar at post office 2 days after receipt.  I did not order it, do not want it and will not pay for it.  Please stop sending me a bill and please remove me from your mailing list. This has happened 3 years in a row. Why does it take so long for your company to receive a returned item?  I will not pay.  REMOVE ME FROM YOUR MAILING LIST.