National Diabetes Association trying to get personal information, Internet

Got 2 calls from these foreign people.  They "sell" diabetes supplies but you have to give them your information such as social security which is the medicare number - they want to talk to the person who has diabetes and I said was the one the had to talk to.  that is how I found out the want all you information.  I suppose that will try to get you social, address and credit card information.  Don't think it is a good idea to give it to some one who calls out of the blue. epically when both of them could not really speak English. I am not even sure the National Diabetes Association is real.  Domain name registered Dec 2010.  they don't answer there phones, there is no forum - dead link.