OnePlus India — I'm complaining about very bad service provided by one plus service centre

Address:

One plus service centre , VR MALL, ANNA NAGAR, CHENNAI, TAMILNADU.

I, anushree, submitted my phone(OnePlus 8T) to authorized one plus service centre at VR MALL, ANNA NAGAR for some display issues( single green line on screen). They said me to submit the phone and promised me that they will repair and return it in 7 days. On enquiring after 7 days they replied me that they dint recieve the new stock yet and it may take another 1 week. On calling them after 2 weeks they are now telling to wait till next month because they dint recieve the stock yet. I'm in urgent requirement of my phone now, how do they expect me to be without phone for another month? When i asked them on 16 sep, if my phone will result be ready in 7 days they should have clearly said me then that they won't get stock for 1 month. This is not the right way, them telling me that repair will be delayed after they have my phone with them. Worst service ever.