What happens if developers website's hosting account suspended where you verify purchase code.

I bought this app https://codecanyon.net/item/android-online-live-tv-streaming/25587728
on 25th Sep completed on the same day and published it. Google play console took 5 days to approve the app.
this app uses a backend where you have to verify your purchase code as I have already done it on 25th Sep. yesterday I ran a campaign for my app but today I noticed I was receiving 1 star and people were complaining that this app does not contain anything.

when I went to check it’s backend I saw it again asking me to verify the purchase but when i did it says this https://prnt.sc/ur8lhr I contacted the developer but he never replies back to your queries. he always says contact me on my email but he never reply there.

when I checked his website his hosting account was suspended and you can look here https://prnt.sc/ur8lhr
and here
both of his domains not working of course he was using the same hosting account for both domains.

So my questions are:
who is responsible for all of this?
who is responsible for all the hard work that I put into this app?
who is responsible for the money that I spend on my campaign?