Skype. We recently moved house and switched broadband providers. My Skype still works well, but

Question

We recently moved house and switched broadband providers. My Skype still works well, but my wife's is now unusable when she calls a land line. Everything is ok at her end, but the other party hears her voice very faintly if at all, and only after a 5 - 10 second delay. Headphones and mike test fine with Windows test feature. Skype-to-Skype calls are fine.I'm hard-wired and she is wireless to our broadband router. She has an excellent connection at 54Mbps. No signs of connectivity issues.