Google Smule Inc review: google smule inc charges per month 1

I have recently noticed that a charge of Rs.55 is being made to my credit card American Express every month for which I never authorized. I am giving recent detail of Oct Month like this every month it is being charged. Please stop charging to my account. I already intimated American Express to investigate.
OCT charged detail

Google Smule Inc -[protected]
23/10/2017 Ref no of transaction --172980006000010011645 Rs 55
The same is being charged every month.
Please stop charging to my account via american express credit card.
My email - [protected]@yahoo.co.in
Best regard
Asit B Mittra
Mumbai India