iPhone 7 garbled calls

I purchased an iPhone 7 pre owned through VM. Looks to be in good condition. Everything works except for calls, both facetime and cellular. There is extream static and half the time it is garballed...

Ohio State Buckeyes Court Bamboo iPhone 7 Case

Manufacturer Direct Item Special event items are produced by manufacturers only after the outcome of a game or event. These are advanced sale items and will ship immediately after they are received in our warehouse....

North Carolina Tar Heels iPhone 6/6s/7/8 Clear Case

Manufacturer Direct Item Special event items are produced by manufacturers only after the outcome of a game or event. These are advanced sale items and will ship immediately after they are received in our warehouse....