Please deliver what I paid for.

I often order online because of the convenience. But have discovered a trend of paying for items that does not arrive. The bags are closed and once I open them and review my order against what is delivered, there is something missing. Yet I paid for it. I also pay for packing (service fee) and tip the driver. (online). I have decided to not use your service anymore. A single event can be a mistake, but this is becoming a trend.