tai_renee I looked into the Cellfish TOS and this is what I found:
Fees and Other Charges
CELLFISH may impose premium fees ("Pricing") for certain features of the CELLFISH Services and any applicable taxes. By completing the registration process, you authorize CELLFISH to charge the appropriate fees and taxes for the CELLFISH Services to your designated credit card or directly to your wireless account invoice (or deducted from your pre-paid balance). (If fees are charged to your wireless account invoice, we may provide your carrier with your applicable Account Information and Transactional Information in connection therewith.)
If you select a subscription plan, you authorize us to continue billing you each month in accordance with the plan until you cancel the subscription. Cancellations may take from twenty-four (24) hours to ten (10) days to become effective.
In addition to any applicable subscription or other fee for the CELLFISH Services charged by CELLFISH, your wireless carrier's messaging service rates apply to your outgoing messages, our confirmation messages and all subsequent correspondence. Your carrier's fees also apply to the messages sent between you and CELLFISH as part of the sign-up, HELP and opt-out processes. You agree to pay all charges incurred by you (or any user of your wireless device) in connection with the CELLFISH Services at the rates in effect when such charges are incurred. If CELLFISH does not receive payment from your designated payment method, you agree to pay all amounts due upon demand by CELLFISH, carriers or other entities operating on its behalf to provide the Services. Your carrier may impose message or charge limitations on your account that are outside our control. Please contact your wireless carrier for information about your account. If any of your billing information changes, it is your responsibility to update your Account Information.
You might want to check with your carrier and explain to them that you accidentally filled out the offer more than once and maybe they can help adjust your account.