I'm in a similar boat to you. I placed my order for a model 3 last Monday. I have paid the £100 but not completed the order - I have paused at the stage of uploading my drivers licence so as to hold the order until the new M VIN number is available for the 2021. When you contacted Tesla to unassign your order, did they give any indication when the 2021 might be available? I called them yesterday and am waiting for a call back. The reason I ask is that I'd like to complete my order, guarantee the new VIN, but not wait too long and end up at the back of the queue
Guess no one has the definitive answer to this, but if you know anything it would be fab