Legally they can not fire you due to daca, as long as you have proper papers they should not fire you, the only problem is that some companies do background checks and they might find if you had credit prior to daca a SSN that is not your, to fix that update all your CC and also contact all 3 credit agency's about your new SSN so they can update all info and remove what ever number that might be showing in your credit reports, hope this helps