Suit for recovery of outstanding dues

Dear Expert,

Our Company installed water coolers in the year 2000 for one of the State Govt offices in India. The said State was bifurcated and Parent State paid their dues and took the stand that 39 of the 100 sites fall in the newly formed State , Payment for the same would me made by new State.

Accordingly we started our follow up and writing letter to them since 2000 to till date for payment, but all our efforts went in vain.

To our letters their are responding but not directly, they are writing inter department letters and CC to us.

In those letters they are admitting the allocation of budget for our payments and enquiring why payment has not been made, but they are not making the payments.  We have sorted those letters thru RTI. 

1.      Can we file suit for Recovery of our dues, as it is time barred, but cause of action is continuous but they are not intimating us directly.

2.      Can you pls provide any citation for the same?

Pls guide.