sever ties with (someone or something)
To cease associating, working, or communicating with someone or something. Sarah severed ties with her family when she was only 17. We decided to sever ties with the company after their horse-meat scandal became public knowledge.
sever ties with someone
Fig. to end a relationship or agreement suddenly or completely. The company severed its ties with the dishonest employee. John has severed all ties with his parents.