I stayed at an arts community/hostel focused on the environment that lent us these lovely metal takeaway containers like this https://www.amazon.com/dp/B001M5SOS2/ref=cm_sw_r_cp_apa_fabc_7FVKJE6VZ65EG3YAZBSQ. I know that the person running the place basically just kept telling the restaurant owners to use her containers and they learned over time. This place is on a tiny island in thailand where it's easy for people to remember their customers, so this may be much harder in a city, but maybe it's possible to bring the containers and order takeaway while you're there, rather than on the phone, and make it happen.

We all do our best and that's all we can do. Try to count the things you do well, and try not to worry about what you can't control. Easier said than done if course.

For your lunch, try a tiffin. You can also use silicon cupcake liners to hold small items, like nuts or grains, etc.