1. I send you BTC using address for which I have a private key
2. I sign message by Crypti team using private key and reedem Crypti coins to address X
3. I complain to you that I have not received my Crypti coins to address Y
Let's say you signed a message "X". The Crypti team will have a copy of your signed message and can send this to me. This will be proof for me that you claimed "X".
You won't be able to trick me into believing "Y" because there's a signed message that says "X" and the only one who could sign this is you. So it's clear that you signed "X".
1. I send you BTC using address for which I have a private key
2. I sign message by Crypti team using private key and reedem Crypti coins to address X
3. Crypti team instead reedem coins to address Z
If the Crypti team reedemed Crypti coins to account Z then I can ask them to show me a signed message that says "Z". Again, they won't be able to provide this message because you are the only one who could sign this.
In above cases, you have no way to prove that either me or Crypti team cheated.
As explained above, I do have a way to determine which one has cheated.