I only gave to the United Way through my job when I was assured that my selected charity would get the money. I got a letter from that group, on their letterhead, thanking me for the donation, in the amount I intended. That’s the ONLY way I’d ever give to UW.
I’ve heard that they deduct such contributions to that charity from the “general aportionment” of generic UW contributions.
I don’t know if that is the case. I gave the same way you did, to a selected charity.