Hash Engineering wallet works fine for me, have done a number of transactions, I have a very small data allocation in my payment plan and it never goes over. The camera QR scan also checks out well.
(the instantX has been removed for now, it worked on older versions but was buggy)

Edit: I noticed some comments about bandwidth usage being high, but it appears they leave the app going in the background 24/7, I always shut it down immediately afterwards, why leave it running eh.

Tip: Check you have visible peers connected before sending any dash, would be a good addition by hash engineering if it warned that you have no peers present after clicking send as an error check.