Bad to worse experience

I took out a data contract with Telkom in March 2015 which came with a portable wifi router and now i see the battery on this device is swelling. I mean how is this possible? We follow all the instructions on how to use the product and charge it and this happens? As if the quality of the product being poor wasnt enough, i went to the telkom store. I was told to incredible connection or gadget shop. Gadget shop said they dont keep this. Incredible connection also dont keep it and even pointed out this was a telkom product even though its Huawei. They expect me to run around like a headless chicken when their product wasnt even good to start off with. I am now unable to use my router which is causing an interference with my needs to be connected on my mobile. This is absolutely frustrating.