Direct tv scam

There is a guy calling people claiming to be a representative of direct TV. He is asking for your bank account information. My grandmother received this call twice. The fist time she was not naive enough to give him this information. A few days later the direct TV installer was present at the time of the call. She told him to hold on and she would let him speak to the installer. He quickly said "oh no, no I'm sorry I have the wrong number" and hung up. Please don't become a victim of this scam. I think they are trying to scam the elderly community.