Maybe the conference will be a motivator for her to finish. Sometimes people find it easy to make excuses virtually but in person, they perform better. So, my fingers are crossed!
It's a good idea in general to never pay for anything wholly in advance, particularly services. I advise using the deposit and installments based on approval system.
If I work on a one-shot project, that type of pay plan is usually included in my proposal and then contract. It's not just for the customer, it also sets my deadlines for me and lets me know how to plan my monies.
And, this is no guarantee! I used a vendor a couple of years ago, had a similar payment plan, and she left money on the table and disappeared. Truly, one day, I just couldn't reach her by phone, email, snail mail. I needed her to do more work to finish the project, and ended up having to hire others to do it. (really hard!) I can't imagine someone leaving money but she did. So, the one good thing is that at least we were able to use what we owed her to complete the project.
