Solved

Tokens deducted got no engines

Just purchased some engines and the tokens were deducted but the engines were not added. 
Please see to it.

Hi Nayan, you purchased parts instead of engines. You'll need to make sure you are carefully checking what purchase you are confirming if you'd still like to purchase engines.

Sorry I made a mistake, will try to be carefull next time.
Thanks

You're welcome!