I lived in Singapore and while I was there, I used MyRepublic's mobile plans. The plan I was using was $24(SGD) a month for 17G. Rarely had connectivity issues

I lived in Singapore and while I was there, I used MyRepublic's mobile plans. The plan I was using was $24(SGD) a month for 17G. Rarely had connectivity issues though for the most part, I stayed in the more populated areas so I may not have had the same connectivity issues as you. One of the nice things was that each telco would keep changing their plans to be better and better so it paid to pay attention and change plans whenever a better one came along.