Security was very Rude

I got to the store with my 4yrs Son to returned the bicycle I bought on the 16th Dec at about 5:15. Went to client service I was second in line I got help after few minutes. I returned got a voucher told the ladies that I still needs a new one I will rather pay the difference because my son would be so upset if we leave the store without on. The time was now 5:40 these Guy approach me telling me with attitude tht I must just finish and leave the store as it is CLOSED. I answered him polity and said must no say that as I got in the store in time and that because of that am a customer and should be help! Eliot security told me tht as much as am off for duty their also want to leave as well! This Guy was to rude n when I checked at tellers there were many customers waiting to pay. I also checked for floor assistance and the was no one because the bicycles on floor was for Girls only !! I so wanted to get out of the shop with it because I was there on time. And their are suppose to assist all customer inside.i felt to complain but noticed that I won't be taken serious as it seem tht when is 5:30 all just wanna leave no matter the customers needs and the fact that I arrived early.