i was trying to get rid of a lot of jewels i have in my inventory, so i went to tonilia in the riften sewers (the one that buys stolen goods) but she keeps nagging on about upgrading my thieves guild armor, so i brought her the entire set, which didn't work, i brought her one item, which didn't work, i tried the previous things by equipping the items as well, didn't work...
all i get is the conversation option 'what if i don't have the armor?'