called my cell phone, hung up after 2 rings

It's Wal~Mart Specialty Pharmacy

I got a call from this number to day.They wanted my birthdate I ask them why .The man said in order to send my medication.I said i have no meds out there and who call this in for me ?He said due to the privacisy act he could'nt tell  me so i said due to the the privacisy act that i could'nt give him my birthdate and politely hung up.