Same problem in Africa, just for different reasons. Cheap aggregator routes into Kenya get you "delivered" receipts for messages that never touch a handset — you only find out when conversions come back flat.
Only fix I found was going direct with a local provider and eating roughly 3x the per-SMS cost. More expensive, but at least you're paying for messages that actually land.
Only fix I found was going direct with a local provider and eating roughly 3x the per-SMS cost. More expensive, but at least you're paying for messages that actually land.