Computerized Billing system at local store hacked while shopping for food

The domain investor avoids going to stores with computerized billing systems, because the computer is hacked repeatedly to frame her as a cheater.
This causes confusion for the store owner and the shopper
Again when the bill was manually calculated at local panaji store, it was Rs 349
The items purchased were
3 breads, Rs 33 each Rs 99
4 moonfills , Rs 15 each Rs 60
1 frozen vegetable – Rs 60
3 digestive biscuit Rs 20 each, Rs 60
1 oat biscuit Rs 40
1 oat cookies Rs 30

Yet when the printout was taken the bill was showing Rs 425
3 breads costing Rs 33 each were priced at Rs 99 together yet the printed bill was showing Rs 165. There was another item where the same problem was faced.
In the list which shown on the computer screen each item price was ok
The shopkeeper kept taking printouts, trying to figure what the problem was, his assistant also calculated the amount as Rs 349, yet the computerized results were a problem.
This is a problem which most shop keepers do not realize and may lose money.