More often than not, companies treat credit cards as water, drinking as much as they can, whenever they want, and don't really care about the customers. This puts the customers in the position of having to not infrequently dispute erroneous charges on their credit cards. I've had to do that about 5 times this year. In every case, I was found in the right. If this causes consternation for some company that wanted to steal my money or hold on to it when they shouldn't, then that's not my problem; I'm already due more for the time I had to wait and then to dispute it. I always contact the offending party first, but I only give them one chance; this is far too common of a practice for me to spend extra time on it.
In the case of Tesla, I would treat them the same as anybody. I would contact them and ask status after two weeks (since two weeks is more than two paycheck cycles in my industry, so one week would have been enough, and a second week to handle any mistakes or delays). If they don't satisfactorily resolve it within a few working days, I'd then follow up in other channels. In this case, other channels is credit card companies.
Accounting issues? The accounting issue is that money owed someone isn't just paid. If it's owed, pay it. I can understand it taking regular time to process -- a few minutes, hours, or even days. As you explain, there could be allocation issues with moving cash flows around. If it is a business that deals with consumers, then it's essentially the same as a payroll account -- it has to be made available for regular business, just as receiving money has to be made available from customers when they buy something. So, I compare it to the payroll accounts of my employers -- they pay me weekly, and therefore I'd expect refunds to be paid at least weekly as well.
If it is a capital expenditure with contractors, then those are whole projects with huge timelines, and that's a totally different timescale. In my personal life, I'm thinking of the solar panels being installed on the house and the timelines for those payments. Also, any business that negotiates particular terms with particular vendors has its own set of rules. But, that's not the consumer side of the business.
Model 3 buyers aren't going to be as forgiving with their money as Model S & Model X buyers, simply because they have less of it. There can be expected a different approach from those different types of buyers.
Agreed. But, I think that's the "extra week" I gave them in my description above. Week 1 was a long time. Week 2 I give for "human element". That's it. Even so, sometimes a second week is considered way too much.