cgst , sgst or igst

i am regular dealer in chhattisgarh. bought goods of rs 5,00,000 from gujrat from company "A", he charged me igst. "A" told me to sell goods to chhattisgarh customer "b" in zero value for sample. now i have to recover amt. of rs. 5,00,000 from mr. "A" . now what to give to "A". sale invoice or debit note". cgst will be charged or igst?