Price mismatch scam

This is third time this is happening with me in super market. (Not in the same one) I went to this newly opened super market to buy things. I was trying to buy refine oil for which the price tag shown in the mart was 147 and during the bill generation it showed 163. When i confronted the manager he just asked the cashier to return the remaining amount. He didn’t even take the tag out. I would have attached the images but it’s not allowed here. Please always match the price in the bill with the tag shown in the marts.