Advertising "Free " Mobile Deposit

Bank has been charging a per deposit fee of $.50 per deposit, with no charge for the first 5 deposits per monthly cycle. Bank plans to make this service "free" by eliminating this per deposit fee. There are usage and carrier charges that may be charged and we include a footnote about this. For advertising purposes, can we still refer to this service as "free" even though the customer may be charged usage or carrier charges from their mobile provider (not the bank)? Just want to be sure we are ok using the word "free" to promote this service. Thanks.