I had vodafone and have changed. I had a lot of problems with them. If you just need a sim for a couple of weeks you should go in one of the "locutorios". It's a phone shop where you can use their computers as well. They are normally run by Moroccans. They have good sims for phoning abroad. I have llamaya. I have had no problems with it and its only a few cents a minute to phone abroad. It's free from llamaya to llamaya too.