I used withholding tax money to keep the doors open.

The option you have is sitting down with the IRS and working out a deal with them. If you want to stay in business that is your ONLY option. They can actually be quite cooperative if you are. Show them your financials, prove that you're having trouble paying the withholding, and then try to work out a payment plan with them. If you show a willingness to pay it and work out a plan, they might even be nice and knock off some penalty/interest. (Whatever you do, don't file the returns late, even if you can't pay. That's an extra penalty.)

The IRS is not much into you using withholding to run your business. Even if you don't like the IRS, and most of us don't, that's actually your employee's taxes you're using. If that's what it takes to keep your doors open and you can't pay them, then you can't really run your business. You can only get away with that for a short time before it comes back around on you.

I've worked for a lot of small companies which are not doing so well and watched it happen many times.