Spark Driver review: Spark delivery service for walmart

I placed an online grocery order at 11:00 a.m. for delivery with a 3-hour window. My delivery time showed between 11:20a.m. and 2:00p.m. I received an email conifrmation. At 1:55 p.m. I received and email informing me that my delivery was delayed by "less than 45 minutes." Mind you, this was only 5 minutes before the 3 hour window expired. In this same email I was told I would be kept updated. At 5:55 p.m. I called Walmart Customer Service to find out what happened to my order because it was well past the delivery time and I had no further updates. Of course, you must now get past the Guard Dog AI system which is terrible! It was like an act of Congress to be able to speak to a human and the AI kept telling me it could resolve my problem. Not. When I finally spoke with a human I was told the driver had a personal emergency and my order had been canceled! I never received any information that my order had been canceled. When I told the rep I would be canceling my Walmart+ membership she transferred me to a Walmart+ retention employee. He was very nice and fully understood my frustration and apologized. I was unaware that Walmart deliveries were made by Spark AND that Spark employees pulled the orders as well. I thought the order fulfillment was done by Walmart employees. That explains how so many of my orders are wrong and substitutes are nowhere near the items I ordered. A big faux pas was when I ordered buttermilk and it was substituted with whole milk. How are those two things alike? Recently I ordered cold medicine that was specifically made for diabetics and people with high blood pressure. The employee substituted it for Great Value brand regular cough medicine which was full of high fructose corn syrup, something I, as a Type 1 insulin dependent diabetic, could not safely take. Do these people not know how to read? It could have lead to a serious complication for me, esepcailly if I hadn't looked closely before taking it. I was very sick. There needs to be better supervision and training of these employees and I refuse to continue to pay for a membership when I cannot receive the services I am paying for.