But you receive some? Do you receive texts just fine? Do you notice any patterns? Certain time of day, certain people with certain carriers?
Have you tried restarting your phone and reinvesting your SIM card? Did you get a new SIM card when you got the new phone?
I just tried one trick that helped me with missing calls. I went to settings --> Carrier --> change to manual --> select Koodo. No missing call happened since then. You could try on your phone and see if it helps.