Up until about 18 months ago I had no problem with coils and batteries. I don’t know what has happened 3 out of 5 of these coils didn’t work. I have brand new evo650 sticks that keep failing. They work for about a day then just stop. When you have given up smoking the last thing you need is for the device that stops you from having a cigarette keeps failing to work. It is extremely frustrating as I have a 3 year old battery that just keeps on going but a new one from yesterday has completely stopped working. I have lost count of how many keep doing this. I did have an parcel where I was going to send the failed ones back but never did as they just kept failing and it would have cost me about £20 to return them all and they haven’t stopped failing yet!!