Someone else's bills mailed to my address

Hi, I continue to get monthly bills for someone else mailed to my address. I don't know if this was a prior owner, because I am the first owner of this townhome. This townhome was a model home, so perhaps there was service attached here before I moved in. I have written "RETURN to SENDER, Recipeint not at this address" on the envelopes and put the bill back in the mail. I've done this mulitple times over the last two years, but the bills keep coming. How can I get the bills to stop coming to my address?  (I have Xfinity service in my own name at this address, and my bills are paperless).