Never tell a customer you need to pay an employee.
A healthy business has the money on hand to operate. It is a bad sign that a business is fly by night when they give the I need to pay my guy line. Not saying your are fly by night or not honest but you sound like it when you say those things.
Never tell a customer that you need x dollars in advance to do a job to cover materials.
You do not want the customer to know that $1,000 job that you are only spending $200 on materials. His mind will cause him to wonder why is the labor so high.
Better to say you need half $500 to start.
Then there is the option to get paid as the job gets done in stages. I did a $2,700 job. I got $1,400 after first stage done. $600 2nd stage. $700 final stage. Now I have to add that I did not need to buy $200 for materials until the third stage
Customer happy to pay that way. Without saying the customer knows that this job got spread out over three weeks and I need cash flow and the way no customer wants to pay up front and get ripped off from a no show. She knew that I was only willing to trust her in stages so there had to be a payment schedule. Again unspoken.
Do not be sad that you lost a job. Be happy you lost a customer that had stiff written all over him.