How can i make a formula to determine payment types

I am having trouble nesting and using multiple criteria. I want a column to determine if payment type was CASH, CHECK or WAITING depending on if the cells for Check# and Payment are containing data.

I have attached my shared Google Sheets files here:https://docs.google.com/spreadsheets/d/1lG31qsy8s97OYnrBIK6k3RVR5s1UoxuqntFBJW3_b34/edit?usp=sharing

Any and all help is appreciated