Can a salary structure be revised in a negative way?

A revision of salary[increase] was proposed in CDAC [autonomous body under Deity and GOVT India]. for contract staff on consolidated pay. It was to be implemented in OCT 2012. But that order was published only on Dec 27 2012 but not yet implemented. Another order was formulated saying the structure mentioned in the first order is a general guideline and the excecutive director can decide the salary based on local conditions with the consent of project owners. This order was formulated on March 2013 without implementing the previous order. But even this order was released only in April 2013. Meanwhile fresh contract offer letters were given to the contract staff on DEC 27,2012, whose term was ending on DEC 31 2012 for 2 years saying their salary was being revised as per the first order. But now neither order is implemented and another circular is released in CDAC Trivandrum mentioning the salary for the contract staff which is considerably less than that proposed in the first order. When asked for clarification all they are saying is that power is with Excecutive Director as per the second order [formulated in march 2013 , released in April 2013] to decide the salary. 

1. Doesnt this amount to cheating or breach of contract? 

2. Shouldnt the staff who were given contracts in DEC saying their salary is being revised as per the first order be given the pay mentioned in the first order from OCT 2012 to MAR 2013 at least? 

3. If answer to the above questions are yes then can they then reduce the salary from April 2013 citing the second order? 

4. Is there any Government Orders or Law that governs such appointments in GOI organisations?