Can't have my money back after the trial period

I activated the one-week trial period at Adobe lightroom premium (August 23 to August 30) and the terms were that I would be paid the account of 5,49€ at the end of the period.

But the money was immediately charged to my google play balance and I was not activated any trial period, but directly the subscription period. Now I need to cancel my subscription and get my money back, but I can’t.