poor customer service from gorilla phones

i purchased a used phone from gorilla phones back in December last year. Delivery was quick and all the wonderful. I did notice the battery life or percentage had a 80% life but at the time i never worried about it. second week into December the life of battery percentage dropped to 74%. kind of worried I monitored my charging pattern and read up on correct manor to charge and discharge my device. Come January I saw the battery life drop a further 4 %. I tried making contact with Gorilla phones as to enquire if the 3 month warranty I get, covers the battery. I get no response from the sales number provided, the contact icon that appears on the web page I filled out 3 three times now, still no response from them. So you can take my money but you cant keep to customer promises or even let me know, listen yes we cover battery or no we don't. its really poor customer service on your behalf.