You cannot take blockers long term without additional hormones, whether estrogen (although there would be no point taking blockers if you were) or testosterone, because a lack of sex hormones is very detrimental to your bone density, leading to things like osteoporosis.
How many types of bc have you tried? There are several different types consisting of various different hormones. Just because one has worked it doesn't mean that all of them won't. Having a hysto is another option if you can find anyone who will do it, but again, you'll need some form of additional sex hormone just the same as if you were on blockers.