Stayforlong Overcharged Me $31 and Told Me to Contact My Own Bank

I made a payment for a stay at the Ramada by Wyndham Dalaman hotel through Stayforlong on June 28th. Although the amount that should have been charged was $998, $1,029 was actually charged from my credit card — meaning more money than owed was taken from my account.
I contacted Stayforlong via email regarding this and reported the situation. I was told I needed to speak with my bank, but since Stayforlong themselves are the ones who made the charge, I don't find this response sufficient or satisfactory. I had previously experienced a similar situation with Hotels.com, and in that case, the excess amount charged was refunded to me immediately. I would expect the same responsiveness and speed from Stayforlong.
I am requesting that the excess amount charged to my card by Stayforlong be refunded as soon as possible, and that a clear explanation regarding this issue be provided.