A week ago, my sister had a surgery at King Abdullah`s Hospital and I had to stay with her for a couple of days. While there, I asked visitors and nurses about the correct direction of the Qiblah, and offered prayers accordingly. When my brother came to visit, he told me that I was praying in the wrong direction, because his mobile`s compass points to another direction. Are my prayers valid? If I was praying towards the incorrect Qiblah, should I repeat the prayers?