Hi antonyb,
I think that it is time that you have some your boundaries with this lady and become more assertive with her.It is better not to respond to threats, If you respond you can be sure that she will continue to manipulate you. It sounds as though you have lost a lot by being with this lady so there is no real reason to go back. You could switch off your phone or change your phone number if you are finiding it difficult to ignore these texts and calls, but do not respond or feel that you need to explain why you are now unavailable to her. She wont accept any answer you give her so why bother?
You have found your way out of this unhealthy r/s.

Continue moving forward antonyb and dont let this girl ruin it by replying to her texts or calls.