Does anyone know of any way to ask them to remove your number from their list?

they called me and hung up after I answered as well. I called them back and a recording said "you have reached the united states prescription card dept..........http://www.usrxcard.com/4732 but another website says that it is a front for loan collectors ----"Even though you return the call and you get whoever or whatever company it's actually Portfolio Recovery Services. This is their way of bugging you and checking whether you answer calls or return them. Do not ever return this call, it only validates. Portfolio Recovery deploys these nasty tricks to get under your skin. They are a ruthless company chasing really old debt, it does not matter the amount. They are probably chasing someone who used to have that number. Awful, Awful company."  so I hope this hels anyone else.

call came in at 4:45 pm.  They hung up as soon as I answered.

The same happened to me. Called at like 8 am and hung right up

They called at like 8am.  They hung up right after I answered.

Didn't answer, but ID says Paducah, Ky area