Informing your customers of potential security blocks

So yesterday was not a good day, I had to purchase some stuff using my c/card. Getting to the till with some items, its says restricted card, 2nd time it declines...I was very upset because I know there's funds in my card.Such an imbarresment for me & my kids.. as I had to leave the shop with my child crying as this was the only card I have with me.I called today just to find out that there's a security schedule block that was placed without notifying me about this. Why don't we notify customers about this. This is such a bad experience for me & my daughter ..leaving the items because initially the card declined which cant be because there is funds but for the life of me I am still upset about this. Why was I not informed about this before utilizing my card. Having to leave my stuff & my daughters things... was not a good experience at all. I'm really not happy about this.