Do you have access to your old account on there too? Is there a chance you didn't withdraw everything?
If they're a small company, they could've emailed you a receipt that'll contain a breakdown of the fees you paid.
Sure I have access, I'm using the same account I used in 2019. Here's the transaction in question:
https://s12.directupload.net/images/210507/juiw848e.jpgI definitely sent everything I had bought.
And this is a similar transaction from 2019:
https://s12.directupload.net/images/210507/o4x883gk.jpgHere I also bought €100 worth of BTC, but when I sent them to my wallet, I received €82. Does it seem normal that I received just €60 now? Are the fees so much higher?