Telkom TP link router issue

I bought a new MIFI tplink m7200 (10/03/20)at Telkom store and paid cash, the sales person said i have a 7 day return policy. this device states it can take up to 10 devices and battery life of 8hrs. I connected 4 devices and after a few minutes the battery got drained to like 40% and flashing red.The next day i took it back to the store, then the technician says....charge it fully then try it, so off i go (11/03/20) fully charged , connected 3 devices and after 30 mins red light flashes, battery drained 40% power left and the device gets hot.(12/03/20) return to the store as i don't want the device now, the manager says they would first have to do a test before anything can be done. Not impressed with service what happened to the 7 day return if not satisfied policy, I had an issue from day 1 with pics to prove the issues....will not buy from Telkom again.