Instagram /face book assistance

we are an established online business but recently had our Facebook and insta hacked ,long story but we now have our face book back but cant link it to our new insta profile as the company that managed our socials have it on there company account and don't know how to change it over although they have no problem doing this .
we also want to link our socials to our on line store and trust pilot and I believe using an expert will save us a lot of heartache and stress
Our web site is http://www.thewatchcollector.co.uk we are based in Cheshire UK
we are not experts at social media but do understand it value and having lost all our followers we want our fresh start to be in the right way.
Hope you can help
kind regards Tony