No battery for wifi router available at vodacom shops

I am on contract with a wife router from vodacom. The battery is all swollen up and I went to East Rand mall to buy a replacement battery. I was forced to buy a new router at a cost of R549 due to the fact that no Vodacom shop keep these batteries. The fact that I am on contract with Vodacom and they supp**** this router would mean that Vodacom should have spare batteries in stock. Apparently this is not the case. So I was forced to buy the new router and used that router battery in my old router. Now I sit with a new router that is useless as I had to use that battery