Oscommerce Paypal Integration **losing business while not working**

I have a dire need to get my oscommerce site woring correctly with paypal. I currently have this module installed ([login to view URL],2679) version 1.3. However It isnt functioning properly or somethign is wrong in my paypal settings. I keep getting a 3005 error when testing with paypals sandbox. Ive pretty much had enough with this and am willing to pay to have someone take care of this. Only bidders with experiance or indepth knowledge of oscommerce and paypal need bid. I am losing business while this is not working.