Buying cheap is very expensive and very costly. Don't do it, cheap is costly!!!

I bought a Mercedes-Benz key fob NEC 433 Mhz for R399 a little over two months ago from PMC Jewellery to replace my original car key because it was damaged. I received it in a good condition after patiently waiting for about a month because it was shipped from Mainland China. I had my local locksmith programme it successfully for me for R1800 once the key finally arrived and delivered to me. Today (about two months later), after using my car all day long without any issues (using the same key), I parked my car at home, locked it with the same key (everything was working fine), I then got inside my house and immediately turned around literally within a few seconds to go fetch something that I had forgotten in my car, I tried to unlock my car and the little red light on the key was just blinking when I pressed the unlock button or any of the three buttons on the keyfob. I was (obviously) within the normal proximity to my car but the door wouldn't unlock. Nothing was working anymore although the small red light kept blinking when I pressed any of the buttons on the key. I then used removed the blade key (the emergency key) from the keyfob to unlock the door and the alarm sounded so loudly I quickly got inside the car, closed the door and tried to start the engine quickly hoping that it would silence the loud alarm. To my surprise the key wouldn't turn the ignition, the car wouldn't start either. (My car's battery was not flat and neither was my keyfob's battery because it was blinking each time that I pressed any of the buttons on it. I am dismayed that the key suddenly gave up the ghost and wouldn't unlock my car doors nor turn off the car alarm, it wouldn't turn on the ignition nor start my car any longer even when the little red light on the key was blinking each time I pressed any of the three buttons on it but with no response from my car even when I was trying to do so from inside of my car. I rest my case!