Gram games (gram.gs)
I bought some paid content for the game Merge Dragons last summer. It was £7.
In September, an update wiped my data. I lost everything, including the paid content. I contacted the developer and received no response. A bit later, I won a gift card and decided to just buy the paid content (premium land) again. They also released another section of premium land that I bought at the same time for £4.
A few weeks ago, the same thing happened. Game updated and wiped out my data. Same thing, no response from the developers. Google play support has been no help at all either.
I feel like I've been ripped off and all they care about is getting money from people. I have proof of my purchases and yet no one will help to restore them.
I'd strongly recommend that you avoid giving this developer any of your money.