Discovered it a bit late, but this product has a polythene/plastic layer inside (the surface which is in direct contact with your mattress). When a mattress is compressed (especially the double layered ones which have a sponge/memory foam at the top and coir blocks in the bottom), it will pass air from the uppermost layer through the mattress fabric. This breathing procedure is required for a good sleep as well. Once you put this protector, the underlying plastic/polythene layer prohibits this breathing as air can't come out. This causes discomfort during sleeping and one will get sweaty in high humidity regions. Not sure why the manufacturers never thought about this simple thing (or maybe they just wanted to fool us around).
It's better to get a mattress cover which is thick enough in the outside (without any inner plastic/polythene layering) and use it with care.