Investors say my BP sounds "too good to be true" even though I dropped projected numbers to 30%, what do I do?

Question

I need only 20k to start and can be profitable within a couple of months. With pre-placed orders it can be profitable within 1 month. And I am not able to borrow from friends or family. The only people I know with enough money are my grandparents and everyone in my family has "borrowed" money from them and I know of no one who has repaid them.
I have now had 5 potential investors tell me my BP sounds too good to be true. I have dropped sales estimates by 70% to only 10 units a month and when I placed limited coverage trial ads on places like Craigslist, I got way more than 10 leads. Also that was in only a few cities.
It also does not help that it is a low amount, and in the automotive sector. The last potential investor was actually an investment finder. His investors want investments that start at 5m.

What do I do ? I have even tried to offer 50% of the profits for the first two years as repayment, making the investor millions, instead of a few thousand.

Answer 1

If you're that confident of success, then take use a credit card or two. You'll be able to repay them long before the interest cost amounts to much.

Answer 2

Since your grandparents appear to be tolerent of being taken advantage of (and you haven't yet ??) hit them up for a cool half mill and give them the full guarantee, like "I'll pay you back in 2 months, with 50% of the profits, etc. etc."