ios 13.5.1

after update ios, I cannot use moible data. but wifi is okay. I restored my iphone by using itune (follow apple website instruction). However, when I turn on my iphone 7 again, the screen shown "cannot activate", the only option left is swithched off the phone.

I talked to apple support, and they told it was hardware problem, and suggested I bring my iphone 7 to local service provider. however, the local service provider told it required $A 488 to replaced another refurbished iphone 7. is it fair ?