I called back this number. Recorded message said they are a non-profit collecting for Native Americans and several other charities which they support. I now remember speaking to someone from this number once before and I told them I will not give any personal info (bank acct, credit card numbers) and asked to be put on do not call list. Apparently no one from this number got the MEMO.
No message = telemarketer. I found information showing: Suspected Spam Telemarketing. The number is a 'spoof', so if you call it, possibly won't get through.