Don't take out a loan. Don't restructure your debts. Don't negotiate with your creditors. Don't sell your car. Don't take a loan from your parents. Don't incur anything more than nominal legal bills.
Collect your contracts and take them immediately to your personal attorney and have them reviewed before you attach your own personal credit to your business'. Doing so is almost certainly unnecessary. You are probably just fine.
You are a businessperson, but you're not thinking like one, and you are going to get screwed. When your company's creditors worked out contracts with your business, they understood that they were assuming the risk that the company might go out of business and be unable to pay. That risk was priced into your contract terms.
If people you've done business with are now telling you that you should stake your personal finances on the debts of your company, then, absent some poorly thought out up-front agreement you had with those vendors to the contrary, you're being taken advantage of. Perhaps we'd benefit from hearing more about who those people are.
As for the merchant account: well, the people saying you could be blacklisted sure sound credible, and maybe you should listen to them. But please also note that there are people on this thread saying you should sell your car or take out a loan to satisfy someone else's debts, and take all the advice you get here with a big grain of salt. It shouldn't cost more than a couple hundred dollars to have an attorney explain to you (not your company, not your cofounder) that you are almost certainly not liable for thousands of dollars of company debts.