Frustrated with online shopping

I purchased beer on line that I usually battle to get from my local PicknPay Liquors. When placing the order to collect at PicknPay Boardwalk Richards Bay, it did not allow me to pick todays date and defaulted to the following day, collection time 15h00 to 16h00. I may give them the benefit of the doubt but am almost 100% sure I selected the correct date. So I still needed to purchase some items that I knew were readily available at the liquor store and went to the Boardwalk. On making my purchase I asked to collect my online order and was told it can only be collected at the date and time specified on the order..... surely this is not the case or was the person just not prepared to help me? If I am late to collect tomorrow will I be able to get my beer? So I'm in the shop making other purchases my beer is there, paid for and I cant take it? Very frustrating. My wife is now unhappy as she has a grumpy husband. Shame on you! Are these one of the cons of online orders for collection?