Incorrect purchase

I sent someone to purchase prenatal supplements for me. To my amazement the individual purchased the clicks brand which I never buy because they do not have Omega3. The purchase was made at Kollonade Clicks on the 9th of February 2022, I returned the supplement on the 11th of February 2022 at Clicks Mams Mall. The manager said they do not accept returns on medication although the seal was still intact and I had not use it. I do not want the supplements because 1: there is no Omega3 in the supplements, 2: I prefer another brand and 3: It’s not value for my money. Can I get clarity on why I was not allowed to return the supplements as I would have topped up to purchase PregOmega which is exactly what I use and contains all the essential vitamins I need during this period in my life.