Update: I got a replacement phone today. So it took from Dec10 when the repair centre received my phone until today to get a replacement phone back. That's 37 days. I must have called at least a dozen times, with a phonecall on Monday of this week lasting 47 minutes, where I just wouldn't give up with the supervisor I was talking to, and I really think that conversation helped me get a replacement instead of a repaired phone.
They had told me that the repair centre was waiting for a part about a week and a half ago, but on Monday I basically told the supe that the time that had passed was ridiculous, that they had my phone almost as long as I had my phone, and I kept pressing him to tell me at what point in time does it become too long for them to have my phone? He of course could not answer this question, stressing that they are trying and awaiting a part. I then asked him to let me know what part it was, and he said he could email the repair centre and find out, then, and this is the important part for anyone in a similar situation to mine, I told him to note my frustrations on the email, letting the repair centre know they've now had my phone since dec 10 and how absurd the situation was and request they replace the phone at this point. The supervisor agreed to put it in, and I believe he must have. So given the amount of time that had passed and that I requested for a replacement must've pushed them into doing it. When I originally called Sony early on in Dec I told them to just replace it, and I was told it was the repair centres decision. They rejected that as they believed they could repair it initially, but it seems they will change their mind given the right circumstances.
All in all, the customer service is horrendous, even though they are polite on the phone. They end up telling you lies and giving the run around. They had told me at one point they called me but were getting a busy signal, however I have call waiting which makes that impossible! It's unfortuntae for us as customers that Sony doesn't give authority to the CS reps to replace phones (or so I was led to believe).
Anyways, I'm happy I got a brand new XZU and hope that it's smooth sailing from here on out!