The device lifetime is an input into the design and development process under the requirements essential for design and development. This lifetime obviously gets into your regulatory product documentation, as well as reflects into the records control.
This information is generally not available to the user, and is determined by the organization when a customer complaint is received as in your case. This however does not mean that such devices in use are NOT safe and effective any longer.
Several decisions can be taken in handling such complaints.
1. Refurbish, and assure that the device is safe and effective. Maintain records and inform customer that the device is good and refurbished but is beyond its stipulated lifetime.
2. Offer a newer version / upgraded version of the medical device (if you have) due to the complaint device being beyond estimated life time, at an agreed cost. OR be able to do the upgrade on the returned device and ensure safety and effectiveness. maintain records and keep customer informed.
3. Offer a new model device that you perhaps have introduced as a direct replacement for the customer returned device, which now is beyond estimated lifetime, and perhaps is also obsolete in your range now. The costs of repair of the returned device may not be feasible, or can no longer be supported.