You have 2 separate problems. When the trial date wasn't changing it ws likely because you didn't call UseTrial() at the start of your problem. You must call UseTrail().
The second problem (the days dropping to 0) -- that's because you fooled with your date. TurboActivate detected the fraudulent behavior and and wiped out your remaining trial days. Just extend your trial with a trial extension and you'll get more days.