Desperately needing a supervisor at my place of employment

One of my part time jobs has been without a supervisor for 6 months!

I was attempting to do the supervisor's job for a bit but I've given up now. It's just too hard to do both my job and the super's as well. Plus I'm not getting paid any extra to do that job. I am beginning to feel disgruntled and taken advantage of. I started doing the extra work with the anticipation that there would be a new supervisor soon. It's been six months and no new supervisor. I feel like the company has taken advantage of my good willingness to help out in a time of need.

So I've given up attempting to do it.

I mean how hard can it be to find a part time supervisor in this economy? I have the impression that they are not really trying to find a supervisor.

It's a part time position at a major retail company. If you want more information please contact me via email or private message.