Why doesn’t Google play fair with my cancellation?

I signed up for a free trial but was then chargedI subscribed to the Google Play music service for a three-month free trial, and used the app to cancel the subscription before the free trial period ended. But four months later I realised I’d been paying £9.99 a month by direct debit. When I complained I was told its refund policy won’t cover the first three months of payments as it had been left “too long”. The helper even noticed that my account still hadn’t