Triple Negatives = One Positive?

I have a thing about grammar.
These things just hit me, whether I want to or not; people do it deliberately, they shout when they pass me in the street;  I simply cannot fail to hear every word they say.
It really isn't my fault.

A girl telling her friend that her boyfriend has got off benefits and into a paid job, which she finds good, because now "he ain't got to sit at home not doin' nothin'.

A girl telling her friend about her plans for Christmas: " No way I ain't goin' to no bleedin' carol service".