Snip going to expires but still no reply from cic

[Nitscanada]

I have apply for canada work visa through snip but i have not recieve any response from cic regarding the status of my application .My snip will get expires on 2 september , what shall i do , the process duration is 3 months after snip according to cic but its already 6 months and my file status shows open.What should i do ,if i do not recieve any reply before 2 september my snip will expires, do my file will get rejected or i have to apply for snip again.please suggest what to do