Improve Portal

I have a program that do the following. From an Access db collects data, in a flat table, then upload this to a site (Access as server) by inserting or update records. The site (Portal) is accessible to our customers by using different user names and pass. My problems 1) is that it is not possible to send many records at a time (I get "time out" error) so I have to split the table to be sent in parts smaller than 400 records.I need a solution to this in order to be able of sending more than 2000 records at a time. And 2) Some of the customers said to me that they observed missing results. So I’d like also to search a possibility for direct connection with the Access db located in the site in order to follow what happens there. I could send, after discussion, the local Access makro or db that collects/splits The Uploader file and finally I can give the credentials for the site (backup Site)