I recently bought Pilot2atc, I'm ok up until i've took off, I reach the assigned altitude set by the controller but then I don't receive a higher altitude ?

Something may have gone wrong on that particular flight, but in general, as you approach the initial assigned altitude, you should get cleared to the next altitude, finally getting clearance to your cruise altitude.  IF you're flying a SID, you will need to adhere to those altitude restrictions until you get past the last restriction.

You can set the lead time for these altitude changes in Config.  Usually 30 to 60 seconds is adequate to give you time to set the new altitude.

If you don't get cleared to higher altitudes on your next flight, send the log file for that flight to [email protected] and I'll have a look.

P2A Log files are located in: C:\Users\<UserName>\AppData\Roaming\P2A_200\Logs where <UserName> is your PC user name. 
Portions of the path may be hidden by default, so be sure Windows Explorer has Show Hidden Items checked in the View tab.
 

Dave