Refund of funds

Hello. Today I received a payment notification in the amount of $302.44. 
The number of members of my group has increased, so the price list has grown. It's too expensive for me, so I immediately switched to the free version. When canceling my subscription, I did not see a message about the refund of the amount of $ 302, only about the 57 that I paid when I was in the group alone. 
I'll ask for a refund.
My email adress: tutorofmathonline@gmail.com