I don’t know what to do...

I’ve been working for a company for about 5 months now. I am one of the only people who was an original. I know how to do everything it’s a very simple job. So i know how to do everything i need to do. We have new people coming in through a temp service that make 2 dollars more than i do. I have to train them and ready them everything because our supervisor won’t. I work nights. I get no nightly pay like I’m suppose to. I have gone to my supervisor over and over about my pay for about 2 months now and i always get the answer that she is working on it she’s doing the best she can! So I’ve gone to cooperate asking and they tell me that i have to talk to my supervisor and she will talk with them about it... but the problem with me is my company doesn’t like me. I’m extremely shy and i don’t talk to people because i get scared. So as you can tell I’ve not really talked to corporate much. Only about my pay. But there has been lies on lies on lies about things that goes on my shift. The funny thing is. I used to work alone so how can anyone know what goes on during my shift other than me? So lies. 😒 so I’ve been trying to find other jobs but i just can’t get called back or email and calls saying I’m not the right fit. everyone i talk to tells me I’m getting walked over which is true. I get things left for me that first shift was very capable of doing but just didn’t feel like it. Things i can’t lift. Things that will take days to get done. And then when i don’t do something because of those reasons i get talked about saying i didn’t do shit. I work with someone that used to be on day shift with me and when he came he noticed that i get left the shitty things and that i literally am always up and doing something i don’t just sit around and goof off like they were portraying on day shift. It’s just a big jumbled up mess that unless I’m making more than the people im training i don’t want to be apart of.

EDIT: They have asked a person that’s been here less than 3 weeks to be assistant manager... and he doesn’t even know all i know.

And it’s not like I’m a bad worker? I just don’t get it