Leroy Merlin did this a second time

I ordered 2 sizes of an item to be put in my home. It was advertised as item in stock. I pay for the the entire item and delivery charges. Today I get a la email there’s no stock and only half the item was delivered. That’s not acceptable. What am I to do. I called the call centre spoke to Matthews Nkhahle and was just cut off. I reordered something else so I need this half order to be picked up as it’s a Leroy Merlin product and I need my money back entire refund with my delivery costs. If you don’t have stock don’t rob people. The last incident I waited 3 months for my refund. You left what you brought in a shocking condition at security please arrange to have it picked up. If you didn’t have the product why advertise it and con people into paying then waiting such long periods for my money back. Please sort this out