Why did my €150 Hodl Hodl trade cost me €20?

I used Hodl Hodl for the first time to buy BTC with a €150 SEPA bank transfer.

The contract on Hodl Hodl stated:

Price: 83,789.44 EUR
Buy: 0.00179020 BTC
Pay: 150 EUR

I received the equivalent of only €130 worth of Bitcoin, so this trade effectively cost me €20.

Is it possible that the seller sent less Bitcoin to the escrow wallet?

Of these €20, how much is the seller’s profit and how much goes to the platform?