GST: Is CST paid on closing stock eligible for input tax credit?

You should not be eligible to claim input credit in respect of goods held in closing stock on 30June

I purchase goods from outside the state but sell these within the state. My annual turnover is less than Rs 20 lakh. As I understand, I am not required to get registered under the goods and services tax (GST). But, my suppliers refuse to supply me until I provide them with my GST Network number. Please advise.  

According to the GST law, the following categories of persons are mandatorily required to obtain registration: Persons making any inter-state taxable supply; persons required to pay tax under reverse charge; persons required to distribute input tax credit as an input service distributor; and