Hi I hv already paid from upi transaction ID 315757574274, but I did not get my storage upgraded in phone

You cannot increase the storage size on your phone, it is a fixed size. You bought iCloud storage which has nothing to do with the storage on your phone.

What's the difference between device storage and iCloud storage? - Apple Support

Go to Settings/[your name]/iCloud; what does it say for iCloud Storage?

Go to Settings/[your name]/Media & Purchases (sign in if it asks)/Purchase History. Do you see the transaction there?

How did you pay for it? The ONLY way to rent iCloud storage is to go to Settings/[your name]/iCloud/Manage iCloud Storage/Change Storage Plan.

Then the transaction was never completed.

Then you didn’t, or you used a different Apple ID than the one your phone is logged into.