I've actually had multiple freelance contracts locally but I've never managed to do any of them really. I had one making a business database of properties for a realtor where I couldn't make any progress and just stopped contacting them. I want to email them to apologise but I can never bring myself to do it.
There's a couple of ways to think about this: 1. What's the worst thing that could happen to you if you disappoint someone?...really, there's not much. Also, worse-case scenario to anything in life is you get punished with jail and/or fines. You are in control of your destiny in these cases. Don't think that there's no way out...there's always a way out. You sound like someone that likes challenges - think of this as a challenge that you have to solve. In the end; for what you have invested, what's another $5k (for a good accountant and/or house-keeping of documents) if it solves your headaches and you can stay in Japan? Try to find a mentor or someone who has been in similar situations to you.
The "escape problems" that you suffer from are caused by anxiety and/or depression. It will take a while to train your brain to think differently and come to recognize these situations as they happen. Try to do a bit of retrospective analysis of how you got to your current predicament and what you could've done differently. This will help you avoid similar pitfalls in the future. Try to plan your days out, then your weeks, then even months or years. This will help you prepare for issues that might arise and prevent new problems from creeping in. Make sure you make time for introspective analysis on a daily basis...and try not to put off anything on your "to-do" list for longer than a day or two. You'll feel much better for it.
Lastly, exercise and meditation will help you a lot. Good luck and know you're not alone in these problems!
If it wasn't too long ago, maybe you can make it up to them by hosting a Wordpress instance (or some other low-cost-to-you CRM tech you didn't have to write) and offering a solution to them for free for a year or something as an apology? An apology would probably feel better for you if you had something to offer them in addition to just the words.
Either way, definitely hang out in the Slack! I don't know where in Japan you are, but there's a lot happening in the Fukuoka area, and I think there's a HN Kansai that just started as well. Not sure of anything to the north but maybe there is!
Also, being able to even find freelance contracts locally is pretty difficult, so that's a great accomplishment, keep your chin up! It seems likely that you have the skills necessary to make it work just need to find the right way to apply them.