CID showed Damascus, MD. I answered since I was expecting a call. The person asked for "Waldo." When I told her she had the wrong number, she said she was calling on behalf of some cancer charity I never heard of, and maybe I could help her. I hung up. Sneaky approach!
I would be interested to know if you have a seen a doctor recently for cancer related treatment. I just got a call on my cell phone from this number and have recently given my cell number to a doctor who is treating me after cancer surgery. I didn't answer and no message was left.
More than likely the caller didn't get your number from your doctor, they probably just used a robo-dialer which can call every conceivable number. Hence the wrong number Casey experienced. Just block and ignore their calls.