I have a rule at my store that my employees aren't allowed to "confirm" anything over the phone. As soon as you "confirm" things, companys take that as an acceptance that you want to do business with them. I direct them to HO.
As a retailer, we will ask you if you want to be included on our mailing list for special offers (we have a customer appreciation day twice a year). And it helps track receipts for warranty or return purposes. This info doesn't leave our store. If you don't want to be added, just say no. No need to be angry at us... we're just trying to do our job
I wouldn't do anything over a phone.