Who called from 7814612040

I keep getting calls from this number because they want my blood donation cause I did it once before

Gave blood and the lady asked for my number. Said its for the records and no one will bother me.. get calls from them CONSTANTLY now..
.. Give blood... Dont give your number...

Called and let it ring twice, no voice mail left.  Probably Red Cross as others mentioned.  They call constantly, keep blocking the numbers when I can, they just call from different lines to get thru.

Can't believe I had to look it up twice