roblox model to obj?

hello,
i want to get my character of roblox(yes roblox)on gmod but first i need to get a .rbxm to .obj or something else i could use.
i searched on the internet but i cant seem to find a good converter or program
but i havent found anything.
can you guys help me out?

thanks

Just remodel it with boxes and easily recreate the textures