If you unfortunately have to take your mobile in for repair, please keep the following in mind when you do.

I am writing this from a neutral standpoint, and I worked in the cellular industry, but I've become aware of the underhanded, infrequently-used tactics that I saw during my tenure in 2000 - 2001, now being very rife in the industry
http://www.hellopeter.com/vodacom-repairs-servicing-%5B450415%5D

The Liquid Damage Excuse
Sometimes, cellphone repair sweatshops just don't want to fix your phone, especially if it comes in a second time. Why? Because, the technician is frequently docked on his wages for a comeback, and there are usually some sort of repercussion in the sweatshop, maybe a warning, etc. So it is easier to just eliminate the phone out the equation totally and claim it is liquid damaged, thereby sidestepping the risk to one's salary.

However, due to the low education levels in these sweatshops, and lack of training, many inexperienced and unskilled technicians forget to clean the PC board of flux after they've replaced a component, which then dries, and makes white powder, very similar to liquid damage, it also causes corrosion, which is then causes the phone to fail, and when it comes in, to the untrained(uneducated) eye, looks like liquid damage, usually much to the customer's surprise and vehement denial.

Lies about known issues
Cellphone manufacturers do send bulletins about uncovered bugs and issues, to the sweatshops. If you suspect you are being lied to, demand to see those bulletins, if that fails, contact the manufacturer directly. The internet is a great tool for finding out which phones have issues too, Google is most useful.

Third time in
If you are taking your phone in for a third time, they are obliged to replace your handset for a new one, either of the same model or of an equivalent model. Usually this is a good indicator of a major issue with a handset. Handsets that are in for a third time are usually scrapped.

Backup of data on your phone
Repair sweatshops will not back up your phone. Moreover it is important to ensure your handset is wiped before submitting for repair where possible. Remove the SIM card, and all memory cards before handing in the handset for repair. Never hand in your charger with the phone, and rather keep the battery, and all other accessories with you. The only time you should hand in your charger with the phone is if your complaint is charging related

Software Upgrades
Should be free and should NEVER be conducted at some underhanded back-store cellphone shop. Only authorised repair centres have the correct software and tools to upgrade your handset. Demand to see an authorisation certificate.

My pleasure

The third time in rule applies even to newcomers like HTC. Just make sure you retain copies of jobcards and other useful pieces of paper and it shouldn't be a problem. This rule has been standing since at least 2000 with Vodacom and MTN and specifically, Motorola handsets.

Next time it happens, please give me a call/e-mail/pm, and I can phone their upper management directly and cut their crap for you.