HELP!!! What is he implying by saying “Ain’t my job”?

*Asking for a friend*

The user texts in blue is the guy I’ve been talking to for a bit and the grey messages is the other guy I told to fuck off and leave me alone and he messaged the blue user (My current relationship)

What does he mean by “ain’t my job” what is he implying?
HELP!!! What is he implying by saying “Ain’t my job”?
HELP!!! What is he implying by saying “Ain’t my job”?
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