I get addressed junk mail frequently. You know who it's from, and they have my address on the envelope, but there is no return address. They obviously don't want you to send their junk mail back to them.
Solution? Look up the name of the president of the company and the company's head office mailing address and put it on the envelope. And "return to sender".
Rogers seems to be one of the worst culprits as I get addressed junk mail from them often (ie both this week and last week and many times before.) Though Bell does it as well.
So I Googled and discovered that Guy Laurence is the President and CEO of Rogers. So I'm returning his junk mail to him.