Is it worth repairing an old phone if it's so bad it takes a week to do it? This probably isn't about paying a specialist a hundred thousand yen to extract data directly from the mainboard, but rather waiting a week for the repair shop to receive a spare part from the manufacturer. This does suggest it's an old model indeed and the repair fee is probably a significant portion of the phone's remaining imaginable value, even if it was once a flagship model when new. If it's not a past flagship model, then it's meaningless.
But then again, this sort of plot development fits this particular series. It's not a good plot device, but it's more or less consistent. We read this series for other reasons.