partial payment of final paycheck and expenses

i live in brandon mississippi, i worked for a manufacturers representative firm out of selmer tennessee. feb 31st one of the manufacturers gave them there notice (the contracts are 30 days) march 7th ( our last day was to be march 31st) they layed off 3 of us because of lack of funds after this company fired them. we ( the 3 of us) then decided to start our own company. i recieved a letter stating that i would be paid the final payment on or about april 2nd and to turn equipment samples etc. in to them. this was done march 28th. i did not recieve payment and was told when things were resolved i would be notified. on april 10th i received a check for what they say is two weeks pay. i was paid 4000.00 per month (1,000 is expenes they paid every month) they paid 1,306. less taxes. with this i recieved a letter say that they were not paying me the rest until they had answeres from the company that let them go and myself for business ethics. it seems they feel i had something to do with them being let go. it was not me it was the change in the managment of the company i worked for which made the manufacturer let them go. can they hold this money? and if not where do i start to get payment?