Complex sentence: He continued to stalk her until she decided to take action-enlisting the help of Phil Mitchell to scare him away--but in the end she had to contact Jack's father and step-mother and confront them with his irrational behaviour.
Split into simpler sentences: He continued to stalk her until she decided to take action and enlisted the help of Phil Mitchell to scare him away. When this failed she had to contact Jack's father and step-mother and confront them with his irrational behaviour.