Un-tastefull Makro service

On Friday morning 27 March i visited Makro Cape Gate to buy milk! On my way to the till was confronted by a gentleman/manager that said i may only buy 2 boxes ( i had four boxes) We had some words regarding this on which the person said its Government rules ( which i do not believe as i will explain below) I was then allowed to take the two boxes i bought to the car and return for the other two as discussed with the gentleman/manager, but when i entered again i was literally chased away as a dog! I do not believe that its a government rule because i went from there to Checkers for the other two. Huge stacks of the same brand on the floor for R 1.10 more per box and asked if there is a limit on it and they said NO ! So where does the Government rule comes from ?