Here's why:
* "Awesome job" is a phrase used as an exclamation, so it should be capitalized.
* "getting them to pay up" is a gerund phrase, meaning it acts as a noun. You need a verb to complete the sentence.
Here are some grammatically correct ways to express the same sentiment:
* "Awesome job on getting them to pay up!" (Exclamation)
* "That was an awesome job getting them to pay up!" (Complete sentence)
* "You did an awesome job getting them to pay up." (Complete sentence)