Spare parts not available in SA

I have a router with a swollen battery that results in me not being able to close the back flap The stores tell me they do not sell batteries for routers and do not know where I can get one. So basically I get sold a product with no way to buy a battery and that I have to buy a new router complete. This confirm what I have been told also by many of the cell c and huawei shops. Its like me having a phone on contract and after 2 years being told if the battery packs up I must chuck the phone. This is very poor service.