Go-Phone - I switched on Auto-pay $amt doubled with same Expiry date

I asked for $25 for three months (until Jan 20 2018) to be taken from my Credit Card and then decided to do auto-pay so I wouldn't be left without service. So I switched the button to Autopay On and proceeded to the next form.

I thought I was asking them to charge me every 3 months. Instead, they took $50 and the Expiry date is still Jan 20 2018.
What now? I don't use the phone that much. 
I don't want to call them....HELP