I'm at my wit's end.

I'm a retail specialist and recently a new retail manager was promoted and given the position. She is absolutely incompetent and only got the job because her bff was the marketing manager. Now the marketing manager has left, and this new retail manager is doing everything in her power to make me quit. We simply do not get along. I've been running her department for her for almost two years, and just found out I was blocked by her to go into an Area detail. I went to her new boss, the new marketing manager, and she recommended I go into a field detail as a supervisor. Not the career path I wanted, but it pays the bills. The problem is, there will never be a form 50 in this office for me. I'm literally stuck doing all the horrible odd jobs because the regular management is too lazy to do ecc's or help customers in the lobby. I work in an extremely busy office with 60+ routes and 100k deliveries over 4 zip codes. I've learned how to run the floor, make carrier schedules for 75+ employees, and genuinely like the work. I miss my position at the district, however, and see no sign of ever going back there as long as that retail manager is there. What should I do?