MetaMask Swap spread/fee too high

I am a bit confused.
I swapped 300 USDT for FRONT and my spread was set to 2% but after the transaction completed, I only received 168.254 FRONT (which is a loss of $80 in fees/spread).
I posted that issue in the Facebook Support group (Metamask Community Support) and one of the admins told me that there was a glitch for the wrong price display and it could be rectified by using a webpage (Decentralizednonce).
That webpage wants me to enter my MM password as well as my seed phrase. But I read everywhere to not give away my seed phrase. It confuses me, too. I am sure the admin wants to help but somehow I don’t have a good feeling of entering my data.
Could you please have a look at it?

Thank you very much!