Raid Mosquito Mats not effective anymore!

I have been using their " Raid Mosquito Mats" for 2 years and out of all the anti-mosquito mats I had found theirs to be the best. However the last 2 batches are completely useless. It seems to me that they have changed their formula or have thinned down the contents . This is very disappointing as I tried the Peaceful Sleep Mats as an alternative but they are even worse.