Left to fend for myself

Two year ago, my senior manager encouraged me to move into a management role from my lead engineer role, so I agreed and did it. However, he provided me absolutely no support for an entire year and left me to fend for myself as a first time manager. After a year of being the team manager, I got really frustrated with the lack of support and moved back to being an engineer even though my previous year was considered a success. However, my senior manager then got revenge on me for doing this because he didn't even try to hire a manager and left the manager position open and forced me to do two jobs as both the lead engineer and team manager, which was hell in terms of the amount of work. He continued to pressure me in this way without him or our director providing any recourse until I finally gave up and left last spring. He is really bad at his job, but apparently got promoted based on his harsh management tactics.