Para decir que algo paró o cambió, la manera cotidiana es un negativo normal con anymore al final: don't / doesn't ... anymore. (También lo puedes ver escrito en dos palabras, any more — las dos son correctas.)
not ... anymore, la manera cotidiana
She doesn't work here anymore.
I don't live in Senfarren anymore.
He doesn't smoke anymore.
Pruébalo: Amina moved away last year. She ___ live here ___. (doesn't … anymore / doesn't … no longer / isn't … anymore) Respuesta: doesn't … anymore — La manera cotidiana es doesn't + el verbo + anymore al final: doesn't live here anymore. "No longer" es otro patrón (no lleva doesn't), y "isn't live" confunde los verbos.
no longer, un poco más formal
no longer significa lo mismo, pero es un poco más formal. Va antes del verbo principal, y el verbo se queda positivo (sin don't / doesn't).
She no longer works here.
I no longer live in Senfarren.
We no longer need help.
Pruébalo: In a formal letter: "We ___ require this service." (no longer / don't no longer / anymore) Respuesta: no longer — No longer va antes del verbo, y el verbo se queda positivo: We no longer require it. "Don't no longer" mete dos negativos, y "anymore" va al final, no aquí.
Usa un negativo, no dos
Elige una manera. no longer ya significa el negativo, así que no añadas además don't ni anymore con él.
She no longer works here. (one way)
She doesn't work here anymore. (the other way)
Not both: "She doesn't no longer work here."
Not "She doesn't no longer work here." — say "She no longer works here. / She doesn't work here anymore.". no longer ya es negativo, así que no uses además doesn't.
Pruébalo: Which one is right? (He no longer plays football. / He doesn't no longer play football. / He doesn't play football no longer.) Respuesta: He no longer plays football. — No longer ya es negativo y va antes del verbo, con el verbo positivo: He no longer plays. "He doesn't no longer play" duplica el negativo; "He doesn't play football no longer" lo duplica y además pone no longer al final, pero no longer va antes del verbo.