Why am I being charged twice a month an amount of $19 by smarty cash back.comSherman oaks .com.

[sandypebbles]

Two real charges, or one pending charge and then the actual charge?

The $19 a month is the fee you agreed to when you signed up to get the voucher

You will be charged that every month unless you cancel your subscription 

[arctoph_49]

It's an old issue, unfortunately (there are quite a few threads). Hopefully you didn't accept the $15 voucher twice with two different accounts. It's by accepting the voucher that you agreed to try the Plus subscription, which after 30 days becomes a paid subscription.