Pertaining complaint against selling an electronic good without bill

Last night I accompanied my friend to buy latest "jio mobile phone" that costs 1500 indian rupees to a retailer agent in our city's bazaar. my friend paid 1000 from his debit card and 500 as cash as the process was over. but when we asked for a bill, the shopkeeper said they don't provide bills for this particular brand "Jio mobiles" and he added that the rules are such that they don't provide bills for this brand. he in fact was rude in answering so. I would like to know if there is any special rules for jio mobiles and if not, then what should I do now legally.