Solved

Engine supply failed

What did you try to do?
I bought 2 times 10 engine from the app, I spent 20 coins, but I still have no engines available.
Please refund coins.

Bought 3 engines from website and the purchase worked instead.

What happened instead?
No engines.

Did the problem happen while using wi-fi, mobile data, or both?
Both

Did the bug happen in the app, on PC, or both?
App

What is the model of your device?
Android 8

What is the operating system?
Android

What is the version number of the operating system?
8

Can the bug be reproduced?
Yes I tried two times, and both failed.

Additional comments:

"U bought 2 times parts"

I see them now, but I was buying engines not parts. By the way now the app has been updated, maybe something went wrong with the old app. I forgot to make a screenshot but I didn't buy parts for sure. I'm not so noob, or so tired to made this mistake and report it as a bug.

Ok, i give u the benefit of the doubt

Hi Guido, your account history shows you purchased 10 parts for 10 tokens three times. Please pay closer attention to which items you are confirming purchases for, thank you!