I have filed and have a confirmation number for net filing, however I cannot see a copy - this was done in March? I have not received my refund or assessment.

First, track down your NETFILE confirmation to be sure you filed. Here's how: https://turbotax.community.intuit.ca/replies/3227955

If you don't find your NETFILE confirmation number in TurboTax, you haven't filed. Here's how: https://turbotax.community.intuit.ca/replies/3210262 

When you've got your NETFILE confirmation number in hand, this FAQ describes how to check your status in your CRA My Account or ask for a "Trace": https://turbotax.community.intuit.ca/replies/2647719