Shipping method unwanted option appearing on customers' orders

I have our website set up with automated shipping rates based on the size and weight of the order. It is all done via Eiz to our courier Aramex. The shipping method should always appear with ‘{Aramex} Parcel’. We charge the cost of shipping plus a fixed amount per order to cover packaging costs. Within the last month or so we have randomly been receiving orders with a shipping method ‘Standard’. This is not one that we’ve created and the rate does not equal the cost of shipping - generally it is lower than what we are charged. Has anyone else encountered this? Can you provide me with any tips as to where to go to fix it? I’ve had a look at our settings both through the Eiz integration app and through Shopify and there is nothing there showing ‘Standard’. HELP