I need a consultant that understands front-end and back-end of Shopify & Volusion

General information for the website: WE need consultation and expert advice on shopify and volusion.
Num. of web pages/modules: 0
Description of requirements/features: We have a Volusion website which has the back-end all figured out (from payment, to subscription, to analytics and inventory count). This site, however, isn't "pretty". We have an agency that works only with Shopify and they recommend working on Shopify. They don't know how Volusion works and say it is impossible to integrate what we've done with Volusion to Shopify.

We need an external consultant to educate us on what the reality of the situation is.
Extra notes: We have been working with a Volusion website building out the back end which is quite robust and almost finished. We need to understand the difficulties of plugging in the work we've done in Volusion with Shopify. We need someone who understands the ins-and-outs of both platforms. We need a conversation ASAP.