I just got pulled at immigration for same reason, I've entered 4 times in the last year. Told me this was last time I can enter on visa exempt. Get a visa mate.
As it stands i have 2 seperate bookings,first booking agoda 11 nights 2 pcr, second booking hotel 4 night i pcr. Neither agoda or hotel will give me confirmation letter for 15 days. Now agoda want me pay them also for extra nights to issue confirmation, yet hotel booking for 4 nights non refundable they say! Confused!!!