My question involves a roommate/utility ethics and laws in the State of: Texas

Can my utilities company transfer a former roommate's bill from 2 years ago to my current account (which is a different one in my name at a different address)? I haven't lived at that former address (where the utilities were under my former roommate's name) for 2 years now. In fact, I've been living in a different house with the utilities in my name for well over a year now. However, the co. transferred the roommate's unpaid bill to my current account and said I am now responsible since they cannot locate my old roommate. The lady I spoke to specifically said that they can't find utilities in his name right now, so I am responsible. She said they did research and discovered that I had lived in that house with the roommate, and as such, since they cannot collect from said former roommate, I have to pay his old bill or have my utilities at my current home shut off. Is this legal? My name was never on the account when I lived with my former roommate two years ago, so how can this possibly be legal? They didn't even send me the bill; instead they just transferred it online and tacked the 461.00 to my current account and then taped a yellow notice on my door saying I had to call them that day because they were about to shut off my utilities. I was never on the account with the utility company 2 years ago, as it was solely in his name. I really feel like I am being bullied by the utility company.