I have the Lelo wand large. I don't use it often, and when I take it out, it usually is dead flat. I put it to charge and leave it until the led turns off (indication of full charge with Lelo toys) - this might take you longer than the stated couple of hours. So far had no issues with it not taking the charge or not working afterwards and I've had it for a couple of years with it coming out to play maybe once every 3 months or less.
I personally have no pleasant experiences with Lelo's customer care, only negative ones and they all required their attention with registered products, having the proof of purchase at hand and within the 1 year warranty!!! But it is also true that Lelo has since rethought their company policy and website and all and their customer care might have improved (as in now it is handled by real humans and not BOTs). But I am fairly sure that without a receipt and the authenticity card (for registration of the product) they will not help you even if you say it was bought less than a year ago... Of course, it is always worth a try...
I would advise you to leave the wand in charge for as long as it takes and only give up on it if more than shall we say six hours have passed and it still doesn't give lifesigns. Is the led on while charging by the way at least? If yes, I'd say should be a god sign, just give it more time. Also, make sure you use the wand's own charger (other Lelo toys' chargers seem the same, might be compatible, but have lower amperage which means there's less electricity that passes thru to the toy).