@Mohitdhawan I have been in the same position, just earlier this year on home services that I couldn't get the whole package of required receipts - I say required as CRTC mandates them, in your case through the wireless code not sure how it applies to hardware alone, but if you did any contract changes with it, it certainly fully applies.
The code https://crtc.gc.ca/eng/phone/mobile/codesimpl.htm is very clear on the timelines on when you should receive a receipt via email or mailed to you related to contracts - it is not so clear on hardware only, but if you changed your contract at the same time, the code fully applies. I leave you to discuss it further and to decide how much you want to escalate, but I don't think it is unreasonable that you are demanding a receipt if you never received one. Typically if you got it from CSR, you would have got a receipt via email or mail, and in the box it was shipped in, there is typically a copy in there too. I would hope that your payment was on your bill too, but there are additional documents that you would receive including terms, return periods, warranty, etc that you would receive too.
But I take you on your word that you didn't get it, like I said, I was dealing with the same issue of receipts along with contract errors in the changes, and I worked at Office of the President to get things fixed Still not fully resolved.