Oppo Reno4 Z Problems

Anyone else here have the Oppo Reno4 Z or similar device that is having the following problems:

I am with Telstra JB plab

  1. Calls cut out mid call
  2. Mobile data drop outs, have to alternate between 4g and 5g to fix.
  3. Watching videos through chrome can be glitchy and buggy.

I bought from Officeworks and ive had longer than a month but I'm wondering if it would be returnable?