I was fired by a company who was going under so they had to decrease their employees. Then I was asked to stay on for 2 months. The company wanted me to train other employees with different duties of my position. Then they company asked me to stay on part time. I remained part time for 2 years and then the company hired me again full time, brought back my original position and salary and gave me a 3% raise. HOW DO I SHOW OR RELAY THIS ON MY RESUME?

Show it from the date you started till the date you quit or stopped working there completely, no need on the resume to bring any of that up.