1. what is the specific issue which you sent your Proton in for?
2. which branch did you approach, the SA's name who attended to you, will be helpful.
3. how old/mileage is your car when it was sent to the service centre?

Go to tribunal pengguna

Your Proton Preve, is it the low spec model or high spec Turbo model? So your car is in the workshop for 4 months already? That is quite unacceptable to me. I thought Proton being a mass-produced vehicle would have plenty of spare parts, especially critical components (Having said that I am still waiting for the driver's seat replacement of my car which was almost 8 months late).

From my experience, the Customer Service hotline, either through emails or telephone calls is quite poor. THey don't respond to emails and I have sent them at least 2 emails which were never responded to. It is only an inquiry or small complaint but still they don't bother to respond. In you case which I regard as serious since the engine as malfunctioned which rendered the car to be not usable, have you spoken to the branch manager in the SC in Senawang? They should at least provide you with a courtesy car for the loss of use of your car.

I guess you need to call up the Customer Service and pester them to expedite a long outstanding problem that remains unresolved.

You shouldn't sent to Senawang SC because they are totally unprofessional. I have bad experience with them. Tow your car to Proton CoE in shah alam. They are way more professional and after all, it's the HQ and i believe they are able to solve your problem promptly.