Confused between ethics and money

I am 20 Male from Jammu, currently doing Engineering at CU. My parents are very strict and I get very less pocket money, somewhere close 500/month, though they can afford 10x. I am a very techie guy with good editing skills, today I got a offer to make edits and I will get 10K per months. I who urgently need 3500 for backlogs fee and urge for good physique would have accepted it without 2nd thought but the problem is its for a betting app. They said they will increase my salary from 2nd months, somewhere around 25K. This is actually very good amount to change my college life forever. But the inner soul is not allowing for unethical work where someone will lose money because of the advertisements I have edited.

I would have denied it but the only major issue is backlog fee. What should I do?