Did the tech forget to remove the trap?

I have had HSI service for a long time, and had cable disconnected Feb 2013. I order new cable service other other day and received my box. I plugged it in, activated it, and... nothing. I called the installation support number and the person on the phone stated that a tech had come out yesterday to remove the trap. If I hook my tv directly to the wall, I get like 2 or 3 clear cable channels, a couple channels with clear audio but scrambled video, and then 95% total snowy channels. The box will not update the time. The support person on the phone was trying to heavily sell me on paying for a service call because sending a tech out to check if the trap was removed might not solve the problem and the only guarantee would be to pay a tech to come in the house. I live in a condo building with several units and have had the same issue with a tech "removing the trap" and not actually doing it a few years ago. Is it possible that the tech made a mistake and didn't actually remove it? I don't think there is anything wrong with my interior wiring in the house since my internet and phone service work flawlessly.