ALTEN interview questions

Had 3 telephone interviews in french, one with an HR responsible and two with engineers (assosiate and principal). After finding a project that fitted me, they decided to invite me to their headquarters in Paris to meet them personally. Only the date was left to precise. After a week without contact and multiples attemps by me to reach them, they changed their opinion and sent me an email saying that they don't have a project suitable for me. I was left wondering what went wrong.

Friendly meeting. Easy to speak to. They promote their company very well. They promised a certain salary but when having the contract in front of my eyes, it was lower than they had said. When I told them that it was lower than promised they tried to talk me around it which does not make sense. I feel a bit fooled. They don't respect market values and it feels like they try gain as much margin as possible.