You encountered a pretty rough experience, which you could avoid if you had a friend who can speak bahasa. As the matter of fact, sadly speaking, it's important. Although Bintan is small (very small indeed), well, for the foods, I don't find it poor since I can accept it. I believe it's a matter of taste.
But staying in the resort for the whole day? Lucky I didn't do that, since they prefer SGD as the main currency. Here's what we did:
1. Rent a car from hotel for 2 days
2. Going to Tanjong Uban and Tanjong Pinang, hitting the Trikora beach for some photos
3. Looking for local cuisine like satay, nasi padang (it's different than what we can eat in Singapore), martabak (imagine a thick pancake)
4. Hitting the local stores for some snacks and instant noodles. This is fun
3 days and 2 nights. I still prefer Batam anyway.