I don’t understand what should I do now

see if this link helps

If you see No Service or Searching on your iPhone or iPad - Apple Support

or maybe this applies to your phone

iPhone 7 Repair Program for "No Service" Issues - Apple Support

(assuming your details are correct and you are inquiring about an iPhone 7)

my crystal ball is off being repaired.. so why don't you enlighten us as to what the issue is?

Writing an effective Apple Support Commun… - Apple Community