Solved

purchase problem

I purchased 5 x 6 token engines but the engines did not arrive and the 6 tokens were removed

May be you are purchasing parts instead of engines.

Are you sure you selected the Engines tab for engines?

I'm sure also because 6token are 5 engines

Then you actually purchased parts, because 6 tokens are 5 parts but (as you see in my post) you cannot spend 6 token on engines, unless you want to waste them in only 2 engines.
Tap on the "Engines" tab on the right before you purchase.

You're absolutely right I'm wrong I bought the parts and no engines

Hi Christian, I reversed the purchase of 5 parts for 6 tokens.

thanks yunus