My company in Fort Wayne split up, and I was let go. As the main technical guy in the company, I was kept on the payroll for 30 days. (This was in writing)

During those 30 days, I helped to transition the company for thier move to new premises and helped a 3rd party technical firm with some of the settings and locations of data and passwords.

I consulted with the technition right up until the 30 days were up.

Because the 30 days was split by the pay period, I received about 2/3 of the pay at the end of the first pay period. At the next pay period, instead of a check, I got a letter asking me to sign a non-disclosure agreement, and that when they received that, I would get my remaining money.

Am I entitled to the last part of my paycheck? Is consulting to get the company moved considered compensation for my check?

Payment of wages cannot be made conditional. That's a bunch of hooey. File a complaint with your state Dept. of Labor. Did the new company buy the old one? Make sure to tell them when you file what the status of the old company is, if you know.

Even though I have a letter from them stating that I worked until July 20th, (my last day at the office was June 20th) they claim that it was actually severance.

There is a big difference there, because missing a paycheck means that they will have to pay for my lawyer to collect the money, but if it is severance, I have to pay those fees myself. And those fees have already piled up.

The company was not sold, it was downsized.

I'm confused. Did you perform services after 7/20?

I did perform services to them -- On the day I was let go, it was my understanding that I was to be kept on the payroll (I have a signed letter from the employer stating that as the case) for 30 days, but I was not required to come to the office.

The only services I performed was to help thier 3rd party consultants outsource the work that I did for the company. In other words, I provided help by providing information to people he hired to replace my position. I did this 4 days short of the end of my "30 days"

File a claim with the state Dept. of Labor for your unpaid wages. As I stated earlier, they cannot hold earned compensation for a "release".