Have you tried everything? Can you post what all you have tried and failed?
There is almost zero chance that the worms are resistant to all medicines and herbs. Surely one of the other will wipe them out. You just need to be patient and try one by one.
As you see from posts, I suffered for about 6 years before finding a cure from Ayurveda, the other lady in the forum mentioned that she suffered 3 years. So there is surely hope.
Please post all the things you have taken. Also check if you have fissures, piles or other issues which can also cause itching.
I remember reading coconut oil will help a bit. Try using coconut oil in the affected area during night and washing away in the morning. This way the eggs may not get hatched. Do this alongwith other medicines you are trying.