If you hold on and wait, a telemarketer from "Online Pharmacy" will come on the line. They will claim to have an account for you and try to sell you prescription drugs. Viagra, etc. If you tell them to take you off their list, they hang up.
Stop them? Don't pick up a call if you don't recognize the name and/or number. Don't push any numbers. Hang up! Report the call to the FCC and the National DNC. -- Educate yourself, your family, and others about these spam/scam/phishing "snakes in the grass" with their phone calls and e-mails (e-mails with no phone numbers, and addresses that turn out to be drop box numbers at UPS Stores).