I know it's probably not what you want to hear but stop chasing the top line revenue at the expense of your cash flow. That type of business model isn't sustainable and leads to never-ending burnout and stress. Only do business with customers who can follow through on your required payment terms. It's okay to extend them terms but anything over 30 days is a death trap. If you're good at what you do, there will be enough businesses that will want to do business with you on your terms. Let them know you're a contractor, not a bank.