Walmart Pickup & Delivery

Using walmart's pickup and delivery system has been nothing short of useless. Each time I place an order I'm required to place a further subsequent order because my order was mysteriously cancelled. Every single time its the same thing. How do you offer a service that simply doesn't work. I'm an international student and I do not have a car so getting my groceries on time is not only essential for simply having food to eat, but I have no other option but to have my groceries delivered to me. The worst part about this issue is that walmart requires that you pay equivalent sum of money just to have you groceries delivered, as if they haven't just taken my money. This service is honestly atrocious and I cannot believe this continues to happen, I am certainly not the first and I highly doubt I'll be the last to experience such poor customer service. It's as if their service has been created to simply mess up their customers day.