This is not Special Olympics of Maryland. They are a professional fundraising service that organizations will "contract" to solicit donations. They'll also call as the Fraternal Order of Police, the Police Widow's Fund, etc. They charge the organizations as much as 30% of the donation amount. If you want to make a donation, hang up on them and call the organization directly. To remove yourself from the call list, say "All organizations" when they ask which list you want to be removed from.
I receive frequent calls from 301-882-9942 with Caller ID "SOMD" and no one on the line. When I try to call 301-882-9942 to ask them to stop calling, I either get a busy or dead air. Tried Call Block using my Verizon service, but this only works on Verizon local numbers. Consequently, I am going to pay $5/month and sign up for Call Intercept so that I can selectively block up to 20 numbers.
It's unfortunate that we have to take action and pay to stop these annoying telemarketers, but that's what I am going to do.