Noise when connecting call

[RichM]

I have just purchased a recon Samsung S8 to replace my S5. Having moved my sim across (GiffGaff) I have found that if I try to call someone, a second or two after the call is connected, there is a loud feedback style noise making the call unintelligable.  The phone was purchased as unlocked from a major high street chain. Any ideas what could be causing hits?

[Mitzzz999]

I would try the Giffgaff sim in another phone to see if that happens again as a process of elimination to see if it's the network/SIM OR the handset.

or try another SIM in the device to see if that happens again.

if it's the network or SIM get a replacement SIM arranged. if it is the S8 I'm pretty sure you will have a warranty with the retailer not the manufacturer as it's a refurb.

[RichM]

Yes, I put the sim back in my old phone and it works. I've been in touch with the retailer with the hope of getting a reply (thank you Covid19) but just trying to cover all bases.  Thanks.

[Mitzzz999]

definitely the phone then and not the SIM or network. You can check for any software updates available but these places normally get all that done while refurbishing the phone. hopefully they will just refund you or swap it. hope it gets sorted.