My word, that is huge for you. I am 5'2" and have had road bikes in 44 cm (actually a 17.5" Terry), and 48 cm. I have a traditional "WSD" build with long femurs for my height and a short torso. I can't imagine fitting any bike > 48 cm. Of course it all depends on inseam, torso length, arm length, and all that, but at 5'1", you were certainly sold the wrong size bike, as you say.

I think the bike shop should take it back! It's a shame they can get away with selling you a bike that clearly doesn't fit. And then you've had to spend $$ on multiple fittings. That's just wrong, wrong, wrong.

I hope you find a buyer. Posting photos of your actual bike in addition to the link would help a lot. I'm sure it's a lovely bike.