I find it difficult to believe that 'as in normal practice in Punjab, no bilty or transporter receipt provided in case of supply in same city' (assuming you are referring to transport of goods through GTA).
There has to be something to prove such transport is indeed took place. If you have taken transport services directly from truck / lorry owner (instead of a GTA), you must have proofs of payment such as bill of truck / lorry owner, voucher etc. where identity of such truck / lorry owner, vehicle used for transport etc. can be established along-with payment made for such expenses.
Moreover, stock / inventory and associated records - both at end of seller & buyer - can also act as 'corroborative evidence' in such matters.
These are ex facie views of mine and the same should not be construed as professional advice / suggestion.