Not allowed to use trolley

I purchased two pedestal fans for one of my offices. I put the two large boxes in a trolley, paid for the goods and on leaving the store I was stopped by Isaac, one of the employees. I was not allowed to leave the store with the trolley. He has to walk with me to my car, so that he can bring the trolley back to the store. I told him that I had to first go to another store before going to my car. He refused to let me leave the store with the trolley. This is unacceptable. So I picked up the two large boxes, one under each arm and left the store. Do they think I am going to ***** their trolley? None of the other retailers in all 4 malls have stopped a customer from walking to their car with a trolley, not even the other branch of clicks, which is in the Mooiriver mall in Potchefstroom. Where does this store policy come from? I spoke to the manager of the store, but the employee kept chipping in. I am not satisfied that this matter will receive any further action by the manager of the store. This is not the first time this has happened, but be sure, it will be the last.