Gosh, I’ll bet you know most of the answers you’ll get anyway with 20/20 hindsight.
You should have had a contract although even that doesn’t guarantee payment.
ALWAYS get money up front whether it be 1/3 or 1/2 or some other formula.
Sometimes when I do hourly I don’t have a contract but that means I get paid at the end of the day. You shoot you get paid. You do edit or graphics work you get paid that day. You can give them window dubs (I charge for that too) as proof of work done but you get paid every step of the way doing that.
Just because they say they’ll pay you 2/3s doesn’t mean you’ll get that either. They can string you along for months.
Even winning in small claims court doesn’t guarantee and if you have no paper trail they may well claim it was your friend of friend who made the promises, not them.
In addition, I’d do the donuts and spots as two separate jobs. Spots don’t happen until donuts are paid for.
As a business my PRIME DIRECTIVE is to keep the business IN BUSINESS.
I’d very politely sit down with them and say that you must get paid in FULL for the donuts before doing anything else with the spots. If they want to discuss the number of spots that’s a separate deal. I simply would not risk continuing to get nothing. If the 2/3s is a tolerable compromise for you then you should get THAT immediately before proceeding with any work.
In short I’d do NO FURTHER WORK unless some satisfactory amount of money hit my bank account.
NEVER allow yourself to be put in this situation again. Again I’ve done hourly without a contract but that means I get paid at the end of the day. With contract I always REQUIRE money up front.