Refund for unwanted app

Hi I was mistakenly signed up for a workout program with XRWorkout.

the app said it was free to use and when I tried it it turned out to be a subscription app at no time did I see a message asking me to agree to sign up and pay a £30 subscription.

I Have been in touch with XRWorkout and they agreed to refund me the money but then sent another message saying that meta dose not provide them with a way to refund directly!

please can you resolve this issue before I contact my bank and log this as a fraudulent transaction that I didn’t agree to 

thanks Joe