Employment/Labor laws in Indiana

I along with 300-400 other employees were let go on the spot a week ago due to the economy/reduction-in-force. I was offerred a supplemental unemployment plan that would extend my salary for several weeks of pay - between the company & whatever my state unemployment benefits would be I am to receive 100% of pay for X amount of weeks...most employees received lump sums - I questioned why I wasn't getting a lump sum & was told it was because I lived in Indiana & it was one of the states that they had approval for this supplemental plan. I filed unemployment & did as employer told me to - to state not getting a severance, but a supplemental unemployment benefit. The unemployment office said they didn't care what they called the payment....I would not be NOT be eligible for unemployment - even called the state office..Now what? I have left a voice mail message for the HR Manager...I did sign a waiver & release form...but, if I don't receive unemployment, I will not be getting 100% of my pay. Also, I have two other documents from my employer stating that I would be receiving a severance pay & the exact amount....so, I'm very confused right now. Ay suggestions of what I should do next?