Stop and Shop complaint: Nasty employee

On 62121 at 8: 45 am I shopped at your Bayshore Stop n Shop. I do instacart shopping for a living. Unfortunately I have no choice where I go , it’s up to my customers.
I use the self check out because it is faster and I’m rated on my speed.
Today I checked out 7 items at the self checkout. This girl who oversees this area, was very rude to me. I’ve had other dealings with her, but until now I overlooked them. Today was the last straw!! She came over to me and said, and I quote You can’t do instacart here anymore I was shocked. Talk about being prejudiced against!! I told her that other Stop n Shop stores let me and I asked to speak to the store manager. Then she said that he’s the one that told her. I went to courtesy desk and had him paged. I told him what she said and he seemed as surprised as I was. So he called to her and she came over and said that I can’t do big orders there because it doesn’t go through. I was still puzzled, but as I stated before. I’m on a time schedule to complete my deliveries and I couldn’t stay any longer to hear the outcome! I had no apologies to me from the store manager or employee. She had her name badge turned around but I heard the store manager call her Alinda but I asked a cashier and she said Amanda. Regardless, I’m sure the store manager can supply her 1st and last name.
What kind of employees are you hiring? What kind of training do they get? Do they have more than a 5th grade education? What nerve she had to take it upon herself and act like a store manager and tell me what she did!! I worked 41yrs for a grocery chain and I would have been reprimanded, sent home and suspended without pay. I want a response asap from you. Unfortunately I still have to go to the Bayshore store for my customers.
I went to the East Islip Stop n Shop and inquired about the limit of groceries I can can do at the self check out and was told there was no limit. Who the heck does she think she us telling me I can’t do instacart there anymore. I want answers. I want results!!