"Not So Incredible" service and feedback from such a large organization

I placed 3 online orders (all the same special advertised) on the 22nd October 2020. I have only received part of my order to date. I have called on numerous occasions but no one can give me feedback. The items that are owed to me are in-stock at the stores. No one contacts me when they say they will. At store level no one can assist me as I purchased it online and that is different? This is a joke considering the size of company and more importantly having the same trading name. I am a very patient and tolerant person but this is ridiculous. It costs a lot of time and money to follow up on something that is being owed to me.