The StreamLine Mic will probably work for you, but they are expensive, around $250 on Amazon, but you might be able to do better elsewhere. It might be more cost effective just to buy a new phone, one of those listed in a post above. Another option might be through the VA, if you qualify for Veteran’s Health Benefits.
The comments on the Amazon site are interesting. Mentioned is the fact that once paired with the HA’s, the Mic can only be unpaired through the Audiologist’s software. This was discussed at some length in a previous thread about a Bluetooth glitch which apparently has been resolved by a software update.