Rude manager, century city

I was doing a shopping alone i had a trolley i needed somethings from Office London i did not see the note that trolleys are not allowed inside the store but still where was i going to leave my stuff, i asked the lady inside the store if can i enter with the trolley then I'll leave it by the side of the store so it wont stand in the way i did not hear her response i entered with my trolley anyway shopped until the store manager came to me and confronted me that the lady told me not to enter with the trolley i told him I'm alone where am i supposed to leave my trolley, and that time I'm the only customer at the store it did not block anyone and the store is huge he said i hope that's the last item you are buying, i had to confirm that and he told the cashier quickly ring her items so she can get out... wow i never felt so ashamed like that