From January until yesterday I was supposed to be a part time employee (30 hr vs 40 hr/week). I was told that the paperwork was in order. I did think that my pay check was perhaps slightly higher than I expected, but still lower than what it was before January, plus I thought that I got an increase for 2009. It turns out that the HR messed up and had me listed as full time, paying me full time while I only worked part time and now they want me to pay back what they overpaid me. I am not certain if this is correct. I have no control over my pay stub, and I fill in my time sheet every pay period correctly which is co-signed by my manager so I don't feel like it should be treated as my fault.

Thanks!
Additional Details
I guess I am just surprised that there are no checks and balances...I fill in my time sheet for 30 hours/week and they pay me for 40 hours/week...And this happened over 5 months, so 10 pay periods in total....And nobody noticed???

But they did say they will take it over the course of the next few months....So now I will be working full time and getting paid part time...Lovely!!!!!