Is this office politics at best?Long Read?

I'm a field supervisor for a well known security company, and I 'm not sure if I'm being treated differently or just me looking to far into things.Well Ive been working for this company and when I first started the payroll scheduler lady was so nice and sweet, but until a few months ago she has been down right nasty and mean, She will not return my calls whatsoever about anything,I am a supervisor, and I'll call her to confirm stuff with my employees,like time off requests, shift changes, etcand I'll get no phone call, I went and did a discripancy form regarding my check, which is always two hours short, she told me she would correct it, and she hasnt done so, and when I call her, and leave her a voicemail, she ignores my voicemail, and so I did a test, I had other co workers call her, and she promptly their calls, and this has been going on for over two months now..and I'm trying to understand why the change in behavior and attitude what hapenned around that time, and thats when this guy hes a manager, told me to call him anytime, personal, and basically the dude likes me, hes asking different employees about me, whenever a new employee starts working with me they'll tell me he called them for overtime.Now all of a sudden, they want to demote me, and bring me into the office as a Office Adminstrator, where I'll be working in the office with her, and the manager, but shes trying to get me fired, or something..Now the manager guy told me that the human resource lady likes him alot..and so I dont know if they know about our conversation we had about meeting up for coffee, but its just weird that after I talked to him some people in the office started to act weird and funny acting..And even my immediate supervisor ingnores me,(I was told he thinks very highly of me) but when I email him, or call him on his cell phone and leave a message, I get no response whatsoever