>>96386147
So just focus on the wizard from now on. Make it your character's ONLY obsession. If the DM tries to sidetrack you with another big baddie, ignore it and insist on ONLY continuing the hunt for the fool who stole your favourite robe. He shall not escape! HE SHALL TASTE YOUR WRATH! YOU ARE HIS NEMISIS AND YOU WEARING YOUR FAVOURITE ROBE SHALL BE THE LAST THING HE SEES BEFORE HE DIES! BWAHAHAHA!

Seriously though, you have a good opportunity for some good roleplay here. Become obsessive about the thief, mutter about him, ask every NPC you meet for the location of the 'Robe Thief'. Play it to the max, how dare he steal your clothes! Hopefully, the DM will pick up on it and feed you a bone, or at least teach the DM not to steal your character's stuff with no chance of recovery or to keep leaving juicy plot opportunities flapping in the wind. Recover your robe or die trying, it could be epic if it works.