AGENC interview questions

I had two very promising interviews, was verbally offered (and accepted) a position, then ghosted. I had applied for a full time design position here, but they wanted to bring me on as freelance first to see how it goes. They agreed to work around my schedule, and over the phone offered me a fair salary based on my rate, which I accepted. I was told a written offer was coming, but instead got an email that said they weren't sure how we could work together because of my job situation ( I was employed full time by another company, which they were fully aware of from the very first interview, and which I made clear I was willing to leave for a full time offer with them). They dragged out some back and forth for a few months, only when I checked in to see what was going on, and the offer never came. Extremely unprofessional and disappointing experience.