Vet or Expert Attempt Bug

Hi, I got the quest that rewards challenge attempt but it did not open for me. I bought an attempt with coins and still it said I have no attempts left. It has something to do with the fact that it registers my current attempt as -5 coz I Completed 10 attempts before the update. Now even if I acquire attempts it's (-5) + 1 = -4 so it won't allow me to do th challenge.