Unfair treatment - PEP STORE JHB CBD

I was treated unfairly at PEP store in Park Central shopping center next to MTN Taxi Rank, Johannesburg CBD. I went into store to looking for young girls shoes and didn't find what I was looking for and decided to leave the store, as I approached the door your security guard requested to see my laptop bag which I willingly allowed. He then took my bramley hand lotion and asked when did I purchase the item, I explained that I purchased on the 7th March at a different PEP store, the security guard proceeded to take my item, I left the store unhappy. I was followed by the same security guard at the retail store opposite PEP stating that they want to see me. I explained again that I purchased the item at PEP store in Jabulani mall March the 7th, I even showed them my transactions on my bank and suggested that they check their footage they were still not satisfied and told me not to tell them about their camera footage in store. The store manager requested an SKU number which I didn't have as the bag I was carrying is my laptop bag. he refused to listen that I have proof of transaction as I was from work. I feel that my rights as a customer were violated as it came across that I came to the store to shop lift and I still left the store without my item.