I plan to visit Thailand for 43 days. My plan B is to spend a few days in Singapore in the middle of this period and use visa exempt entries. Without knowing why the application was cancelled, I won't apply again for a 60-day visa, partly because time is running short ahead of my trip.
I do visit Thailand often, but always arriving by air from Italy, and never using back-to-back entries, so I don't think the application could have been cancelled because I spend too much time in the country.