You have unwittingly subscribed to a Premium Rate Text Number.
You must send the word STOP to the Premium Rate Text Number you will need Airtime Credit to send this Text as it is not covered by goodybag texts allowance.
Also there should be a Call Centre Number towards the end of the Text.
Ring that and demand they remove your details from their subscription list and refund all credit taken from.
Until you get this sorted out keep your Airtime Credit below the sum they are taking, if the credit is not there they cannot take.
I hope you get this sorted out quickly.