i had a similar thing happen to me.. i have the white multicolore Audra... I know im going to get yelled out but this is what i did and it worked for me..
i got a lint free cloth and some husehold bleach.. i dabbed the cloth in water to moisten it then in a tiny bit of bleach.... i then dabbed the mark on my Audra and it came off ... i then took another cloth moistened with plain water and wiped where the mark had been ... its been fine ever since.... its not discoloured or damaged the canvas as it was only a miniscule amount.. it was just enough to " bleach the jeans
dye" without damaging my bag... its not for the faint hearted but it worked for me...
good luck
x