Shoppers Drug Mart review: pharmacy

Was looking at my high blood pressure meds yesterday and noticed that I was 7 pills short. Went to Shoppers to rectify the situation and spoke to a man that could use some customer service training. He tells me that he is the person in charge, but somehow I doubt that. To make a long story short, the man refused to provide me with the (very pricey) medication I had already paid for. He insisted on me paying for the medication--which, of course, I eventually did. 7 pills for $5.00. Not only did I have to pay full price for the pills but my prescription insurance was not used either. I was getting a little frustrated. So, I thought, just take the prescription somewhere else. I went to Loblaws, and the change was made without much fuss. Then I get home, and phone rings---sure enough it's the guy from Shoppers Drug Mart. He wants to know why I've changed my pharmacy for the (very pricey) high blood pressure meds. When I told him: "I'm the guy you stiffed for $5." there was silence on the phone. I honestly thought that pharmacists were taught to count--as in simple math. I also thought that they could distinguish one customer from another--it should have been a no-brainer that I would change pharmacy.