D-Mart / Avenue Supermarts — Overcharged for items

Overcharged for wheet we took loose wheet of rs. 31/- in 3 packs of 5 kg. Same wheet had overcharged on one counter is at rs. 39.50 per kg. And on another it charged at rs. 31/- per kg

If we are in hurry staff charged more on items even if we told the price of what we have taken.

The complaint is that when we notice the bill charged more at home and call the malad mumbai dmart on same day they accept it and told me no need to bring wheet come and collect the money overcharged. When my husband had visited malad dmart they told us bring wheet and then overcharged money will be given. Why they harrasing customer even staff has committed cheating.
Is it possible after one visit once again we have to visit dmart by carrying wheet for collecting overcharged money.
Who will paid our traveling charges