During the entire payment process I was unable to find any option to add voucher code which I got from benifits section on this app. Can anyone help me?

I'm using the Note 9 today I noticed brown spots under the screen. It's near the bixby button. Can anyone tell me what are these brown spots. What can I do to fix it. Has anyone else faced this issue. 

How can I enroll for Note9 android pie. There are no banners or links in notice section. Am i too late to participate?? Help me

Finally bc

When will Indian S7edge get oreo it's June now still no update