They call all the time, I just tried to call them back and a recording comes on to say they are unavailable, but please leave your name, phone number and we will return your call.   If this is a company collecting on behalf of Veterans, they need to id themselves.   I would contact Veterans Affairs and see if they do in fact solicit calls or have people who call on behalf of Veterans to raise money.   You might also want to try the Legion.
Moreover, in Canada, Veterans get money...they get a certain amount of money for housekeeping, gardening and food.   Why would someone call to collect money for them when they already get benefits from the Federal gov?