I don't think you need the acknowledgement from the charity. I have always assumed that the trustee of the account is checking the validity of the charitable organization's 501 c 3 status before they set up the distribution. That may be wrong but that is how I always thought about it. The 1 client I have who set up a QCD at my suggestion has never sent me a donee acknowledgement and the amount is significant. I have just entered the info from the 1099R and went on.
Tom
Longview, TX