Help needed: Unlocking. Not rooted.

Hi Guys (and Gals),
I've just registered on the site, after browsing and reading posts for a few days. I'm very much an Android tech-noob but also very keen to learn more as I go along...
Here is my dilemma:
After sending my HTC Sensation XE back and forth to HTC for repair 4 times, I've now lost any faith in them helping me resolve anything. Basically, they sent me a replacement phone (supposedly unlocked) but it is locked (eight digits) to an unknown network and I don't know how to unlock it. After wasting precisely 3 months and many hours on the phone with incompetent HTC technicians, they finally informed me last week that my warranty had just run out, that day, and that they would no longer help me with any problems with the S-XE. Nice - NOT! I was furious.

So, here I am wondering what to do next. I have followed a few threads on this site and tried a couple of unlocking methods [ http://xdaforums.com/showthread.php?t=1232107 ] but it appears that these methods work only on rooted phones. D'OH!
My phone isn't rooted and is currently showing S-ON. (I *think* i'm learning some lingo, lol).

I rang a couple of local traders, who said they can unlock it for a tidy sum of £15. I'm not sure what these guys do to the phone and whether it is basically the same as rooting my device?

I guess what I'm asking is, does anyone know how I can unlock this phone myself, without rooting it? Alternatively, would rooting be the only option and which method would be the best option.

I already use a HTC One, so I obviously do have a working phone but I am very keen to get this Sensation XE working.
Despite being quite clueless, I'm willing (and curious) to give rooting a go, if it's the only way to resolve my problem. My fears are that I just don't know which method would be best (and simplest), I'm worried about 'bricking it' and I don't know how to flash a ROM.

After reading some threads here, I have determined how to fastboot (?) my phone and have found the specs, as follows:

***LOCKED***
PYRAMID PVT SHIP S-ON RL
HBOOT - 1.29.0000
eMMC-boot
Mar 2 2012

Current software info:
Android version: 4.0.3
HTC Sense version 3.6

Anyone have any sensible ideas? If anyone can help, I'd be very grateful. Oh, and apologies if I've posted this in the wrong 'section'. Many thanks in advance.
Regards: Undercrackers.

rzr86 said:

if you want to unlock your device to any network then you have to do this first
http://xdaforums.com/showthread.php?t=1661631

after S-OFF in the thread you mentioned go to page 54 in see post #531 on how to unlock it

Click to expand...

Click to collapse

Hi, rzr86, thanks for the info.
I downloaded the latest controlbear, ice cream sandwich from http://unlimited.io/jb_pyramidlocked.htm
I followed the instructions from http://unlimited.io/juopunutbear.htm as far as I could.
I plugged in my USB and managed to run temp_root.bat with no problems but, I ran into problems with the ControlBear instructions and folder.

I'm guessing my phone is 'Stock RUU' but unsure what this is.
I'm not 'HTC Dev Unlocked', as the prerequisite states, but it says in the thread [http://xdaforums.com/showthread.php?t=1661631] that I don't need to be so I'm now confused.

Another point of reference is that there is no ControlBear.exe file to run, in the ice cream sandwich downloaded zip folder.
It contains just a ControlBear [non exe] file, alongside adb, fastboot, MD5SUM and a jb_hboot rar/zip file.
I'm not sure if anything is missing?
Excuse my ignorance here.

The instructions say:

8. cd into the folder where you extracted and run the following cmd:

Note: This cmd returns a blank new line if you have done it correctly.

chmod 755 ControlBear adb fastboot

9. Run ControlBear from terminal - sudo ./ControlBear

Click to expand...

Click to collapse

This is where everything fails me, I have no idea how to do this - at all, so I ran temp_root_remove and set my phone back to how it was before I started.