Cst overahead - how to claim back ?

We are in competitive business, even one percentage make huge difference. Now I need to get the products from other state manufacturer and this other state causing me additional 2% for CST(given form C) . Due to this i may not match with prices with other manufacturer delears and chances to loses the business. is there any way, can i claim the 2% CST back? This first time, we are buying from other states. Please advise the solution for this? Appreciate your reply.