I would take the medical route.
I would have a doctor write a letter saying you have anxiety and any additional stress would be hazardous to your health. Then I would write a nice letter to the elders in the congregation, maybe even all of them, with a CC to WT HQ, and maybe to the CO even, stating that you are under doctor's care and cannot be stressed by any means, and attach the doctor's letter. Thank them for their concern and tell them you will contact them when things improve and you are able. I would send the letters return receipt.
It would be well worth a doctor's visit explaining the harassment, or if you have EAP at work they should be able to provide a letter as well.
WT HQ would probably tell the congregation to back off. It's not worth it.
They can still write you a letter demanding you to meet with them and if you don't show, they can DF you. But if you have the medical issue in place, it might be a good deterrent.
When I left I had an elderly pillar of the congregation mother I looked after. My one goal was to preserve our relationship and not to cause her any more worry at her advanced age. I was ready to do ANYTHING. It didn't come to that but it was a few nerve wracking years when I first left, dodging calls, hiding from the knocks on the door, worried about running into people etc.
Do you know why they are so persistent with you? Usually they save that for elders and servants. Anyway, good luck to you. It will get better.