hello , I bought yesterday a tardis and I donated to get it , I would like to know why there is no donator callsign before my name in the game , thanks.

You can't buy a tardis so I assume you bought a cartridge from the DMU Store.

1st of all there is a difference between purchasing and donating. So no you won't get the donator rank xD.

why is there the donator thing on my profile on this website then? I don't understand the thing

The donator item on  your profile is a badge, it's the badge everybody gets for making a purchase, whether it is a DMU store purchase or rank, it has to be a rank purchase for it to be on DMU, https://swdteam.com/p/uWOAAQgZCQhrPWEcgMuaC7ZsWbEqxjEz is the donator rank, if you ever purchase it or any other rank, go to your inventory and click your rank, click product options, and change rank