Remote pair

I have a very old zenith tv and had to get a new box. Tried to pair the remote for volume and on/off. I enter zenith and go through about 10 iterations and it still cannot give me a code that works. To talk to a technician I have to give a credit card, they claim just $1 but the fine print says an additional $46 plus $46 monthly. This is not customer service. Can anyone help?