No accessories for Cellphones

I bought a Stylo Luna a year ago the battery is swollen and needs replacement. i have been to numerous stores to find out where I can get a new battery and all I get it is "I dont Know" how can they sell a product if they Nr1 dont keep accessories or Nr2 dont know where to get them. I went to other cellphone shops nobody stocks them. Am I meant to go and buy a new phone now