What should I do? I filed bankruptcy last year and now all of a sudden the hospital is calling me and demanding I pay them 23,000.00

Were all of the $23K bills listed in your bankruptcy?

If they were listed, in the bankruptcy, have your attorney call or write them to demand they stop.

First of course never talk to them on the phone, if you did not have an attorney, send them a letter with the case number and demand that they stop any contact.