Controlling settings, permissions, and membership within Teams and channels
Hello Litto
I am V. Arya, Independent Advisor, to work with you. I am sorry as I will be conveying bad news here. Each pair of receiver and the device is uniquely mated to each other and there is no replacement of the receiver. The radio frequency is set in the factory and no two sets are having the same frequency to avoid disturbance to each other. Once you lose the receiver, then connected devices such as mouse/keyboard become worthless. You will have to buy a complete set again.
An advice - In future buy bluetooth keyboard/receiver rather than buying devices which are based on radio wireless technology. You won't face this issue in bluetooth devices. You lose something and that is replaceable.