Tried to get older phone carrier unlocked to no avail

Followed all directions on the website. Nothing worked. I then proceed to chat with an agent. He tells me the device needs to be on the network to unlock the carrier. Basically trying to sell me a phone plan I didn't need or want. I just want to give my older phone to my mom so she can use it on her network. Which I have done before through xfinity with no problem. The live agents online are just sales people. They are not really there to help you.