I autopay every month for my $45 2GB plan. I don't use cards, but I have never noticed any charged calls or texts, since my prepaid plan is unlimited talk and text.
just look on your Verizon web site and took under usage, scroll all your calls and see if any where charged from your account.. they reimbursed me about 12$ cause of this, but its still happening..
Is it the same number or different each time you are charged? Is the contact number entered in the correct format? Were these charges basic roaming charges or international?
I have been on the $45 unlimited plan for a few months now and have had no problems with the unlimited talk and text. You won't be charged for any calls unless your in a roaming area which is rare since Verizon tends to have the best coverage.