puccellino , Jun 21, 2021 : I don't think you can separately buy a new OnePlus case, but you could try talking to customer support. If they say they don't sell them seperately, it might be a good suggestion to give to oneplus directly. You can submit a suggestion following the link below. https://forums.oneplus.com/feedback/
Q1619364161445 , via OnePlus Community App , Nov 27, 2021 : Call me for buy/sell right/left side buds : Mob no. =) TG0WTJDM1G
Allwyn0211 , via OnePlus 7 , Apr 14, 2022 : Hey there i lost my oneplusbudsZ and i have only the charging case left,if ur interested to buy it let me know.