Express Invoice - Express Accounts Data overwrite issue

[Shop4Tackle]

So When I try to import Data from Express Invoice it totally wipes any data already in Express Accounts? Why would this happen?

 

As I can't get the three programs Inventoria - Express Invoice - Express Accounts to connect over my local network (help needed with that if any iMac users are on here) then the only way to get all my data from Inventoria is to go import date from Inventoria in Express Invoice and then again from Invoice to Accounts .... if that makes sense

 

PLEASE HELP SOMEBODY