Galaxy S21 5G

[YeshikaSingh]

The back of my phone is coming loose(plastic backing). What could be the issue and how can I fix it?

[mrug_tangy]

Might be a swollen battery or heat emitting from your phone heating up the glue that holds it.

[Tsogo_sam05]

Hi YeshikaSingh

Please take your phone to the service center to have it assessed by a technician. 

Please go to the below link to locate the closest Authorized Service Center to you.

https://www.samsung.com/za/support/service-centre/

[DatGuy]

Could be a "spicy pillow" - battery swell. In any case, you'll have to take it to the retailer for a replacement. Please don't ignore, the battery could explode if it's swelling and under heavy load.