I can't imagine giving out my bank or credit card details to someone that rang me out of the blue, can you? (a) I don't think they'd call and expect you to do it and (b) even if I really thought it was the people that sold me the phone I'd want to check their number and ring back.
why are people this stupid. I neve give out my imformation unless I initiate the call. I don't give my card to any company that calls me to sell me something period. I don't care who it is. if I want it I would have called them in the first place.