Customer matching with email only

We have had exceptionally poor luck with Connector failing to sync a majority of our transactions.  We use Connector with Bigcommerce, but this discussion should apply to other website platforms.  We use this site as a specific Wholesale Customer site. It is very important that we are able to match all forms of transactions in order to create invoices in QB's for that specific customer. Connector does a great job of creating an invoice in QB's and can even track the next in line Invoice number in our QB's record.  It has the ability to recognize Offline checkouts, which most QB's sync Apps do not.  We have customers on Net Terms which allows those customers to forego the official checkout were they would have to pay for the order.  Everything works great with Connector for our needs with the exception of matching Customers.   

These failed sync's have all been based on small differences in the Customer Billing & Shipping infomation and how the customer chooses to enter that information during the checkout process.  Do they use the registered address info from their account or do they use previous info that they used from their last order that their browser autofilled?

Product syncing has worked great since it only relies on the one parameter to match.  We use a SKU number and it never fails if the SKU is matched.  It's an entirely different story with the Customer information.  After much trial and error, we realized it comes done to what customer info is listed in the shopping cart during the checkout process.  From our back end log in to our site, we can see the Customers registered Billing & Shipping information.  We made sure that our Quickbooks account for a specific customer matched that exactly.  Unfortunately, not all customers choose to or remember to use that registered information in their address book.  Connector uses what they call a 'complex algorithm' to match customers.  As far as we are concerned, it's far to complex.  If a customer makes the smallest change in their shipping and billing info during checkout, it will forced a failed sync.  One example.  We have a customer that uses Coffee House in their business name.  That is how we have them registered in QB's and on record as the official Billing & Shipping address information in Bigcommerce.  With autofill on browsers we have discovered that customers will frequently defer to using whatever address configuration they used during the last transaction rather than the official one registered in their account. The Coffee House customer at one point used Coffeehouse as one word instead of two.  Every other piece of contact info was the identical. Personal name. The first part of the business name. Phone number. Email.  The single only difference was Coffee House vs Coffeehouse.  This alone caused the sync to fail with QB's. We have no control as to how exactly that customer chooses to Checkout.  We continue to request Onesaas to force a Refresh to sync all failed transactions.  This works, but it unfortunately automatically creates an entirely new Customer record in QB's.  We have to make note of each of these and then go into QB's to Merge these 'new' customer records with the existing one.  We've honestly spent more time correcting failed sync issues that we would have spent manually entering invoices into QB's. 

My request of Onesaas is to allow us the option to choose which customer parameter is best to match customers properly rather than their complex algorithm.  It could be one field or several based on preference. The one field SKU option for Products work great for Product matching, why can't we choose to have customers match by Email only for example.   For our needs, in the Advanced Settings, it would be great to Assign Sale to the...Customer Email.  This way we could instruct our customer to simply contact us if the ever had need to change their associated email rather than hoping that they remember to use the exact full address and contact info each time they place an order.

Thank you.