How long can it take to repair a phont

I bought my Iphone 6+ cash from Altech Autopage Melrose Arch in January this year. It has a problem with the camera. I took it in for repairs on 23 July. It is now 5 weeks lateR and no one can tell me where my phone is or when it will be back. How long can it take to repair a phone and how do they expect you to function for this long without your phone especially when you use it for business. The branch referred me to the head office call centre who said they would look into it and gave me a reference number. No one came back to me and when I called back they told me that I had to call the branch as it was not their area and they could not find the reference number. I called the branch yesterday and they did not get back to me. Today they are telling me that they dont have any of my details although they are all on the job card. I am going overseas on business next week and need my phone but I cant get any useful information from anyone. DISGUSTING SERVICE