Anyone know how to solve this problem?

I am having problem with one of the 1HP air conditioner unit from Panasonic. Problem started after about one month after installation.
It seems that it is noisy when the air swing is allow to swing.
Their technicians have made 5 attempts to rectify the problem and till now, the problem still persist.
It seems that they are using trial & error method. Every time, when they come, just apply some grease onto the moving parts and the next time, come and change the air vent. After using for a few days, after the grease dries up, the noise comes back.
Now, the warranty is about to expire...

Written to their Customer Care dept, then they called and want to try to apply grease and replace the air vent again. Really don't know when all these trial & error will end and problem solve.

Really regretted installing the Pana aircon. Some more went and installed 4 units. Include the older set (2 years ago), so, in total 5 units.