Take it as a learning opportunity...
First, for longer stays ensure that you agree up front a fee for weekly cleaning so that you can keep on top of things at your rental.
Second, next correspond by text - keep it on the platform and raise a case via the resolution centre. At least that way you stand some chance of getting payment.
Finally: asking guests for a cash deposit will get you kicked off AirBnB and you will get bad reviews in addition. It's better to think about how you should manage longer term rentals in my opinion.
Finally - $200 seems a low deposit. Remember they don't pay it up front - I would increase the deposit and attract a better class of guest hopefully!