Online pharmacy. do not answer these calls

Online Pharmacy is a fraudulent company with multiple fake phone numbers. They stole my credit card and tried to sell me a prescription that I get for $9.50 for $600. What I still can't figure out is how they got my prescription and credit card. I canceled credit card before they could bill it and that really pissed them off. . I have notified the DEA, local and state police. Also notified attorney general's   offices in Washington State, Louisiana, Tennessee and now Montana.  They speak in an Indian or Pakistani dialect.
Another number they use is(615)724-7999. Maybe they have terrorist as well as pure drug dealer fraud.

How can calls from, "Online Pharmacy" be blocked? They sometimes call themselves US Pharmacy or is this outfit, US Pharmacy, another entity altogether?

Scammers!!!!!!  They want your credit card information only so that they can screw you and your credit.

I got an answering machine at Target that will block up to 20 phone numbers.  It has worked wonders for me.  It's a panasonic kxtg9331 model.