faulty when first used - refusal of warranty

I bought the battery also, because I had also bought a second Makita cordless screwdriver. (In practice, because you do not always have to change drills and bits.) This battery never came but so far in use, because the two-1,4Ah Makita batteries so far always ranged from the trunk. Last week, now the first use and after a short time only half speed and the Makita charger now displays "Battery defective". This is very annoying. Annoying especially because now the first 6 months of purchase and the seller skgames over the rest the 24 months warranty and principled opposition, if I did not teach an opinion on my bill. So doubly annoying.
Hands off!