Then why did you let a third party determine the exchange rate?
Because it's their responsibility to exchange the coins for BLOCK.
We'd have a conflict of interest if we determined the price.
This is pretty glaringly obvious IMO.
How would there be a conflict of interest? Coingateway takes a percentage of the value of the transaction. They could value this transaction in terms of the tokens and have no uncertainty. Then you could set the exchange rate. And if you had done that, you could share the valuation function with us.