What kinda offers your been promoting ?
Ive never used Quora as a traffic source, but from my thinking only certain kinds of offer would work there. I would also think you would get more from providing premium like long answers to questions that are inline with your offers and then link to your landing page, rather than just running ads straight to the platform. Just my opinion tho, you tried FB or Zeropark ?
Make sure your landing page is properly optimized otherwise you may get clicks but you won't have any leads.
And be sure to warm them up properly before putting your link.
I am spending between $20-$30what's your daily spending?
Promoting your CPA offers on quora is is really very great idea according to me, but you should be very careful while promoting it on quora. Because there are lots of chances are there for getting banned.