This whole thing leaves me more baffled than anything. According to the dates, they basically ignored you for an entire year (started ignoring you around July last year, finally responded to a message in late July this year?), and it makes me deeply uncomfortable that you had to reach out under the guise of implicitly inquiring about getting a new commission before they would even acknowledge you (to be clear, it's not your ruse that makes me uncomfortable, it's their ignoring actual clients but responding promptly to potential new ones). I really try to give people the benefit of the doubt, but man. An actual literal year of radio silence is just beyond comment. It makes me so sad.

If I were in your shoes, I'd ask about a refund, given in installments if necessary. It would be so difficult for me to work with an artist who seemed to care so little about me as a paying client that they ignore all my attempts to reach out to them for an actual full year until I have to do something vaguely deceitful to gain their attention.