Problems with shipping prices

[memu]

In incoming orders, the shipping fee is charged at double for products whose stocks appear as stores and warehouses. How can we fix this situation?

I talked to shopifyla but I didn't get any return, that is, the customer orders 3 products, 2 of them are in our warehouse, but the other product is not in our warehouse, since it is from the store, it sends the product from there, it charges an extra fee for buying it from a different place, how can I solve this problem?

(sent price 6,90€)