SLB Graduate Field Engineer interview questions

I went to a job fair and Schlumberger was one of the companies who's participating. I gave them my CV and we had a little chat about myself and my degree. two days later I got a phone call for an interview. the first interview was so general and so easy it is basically to talk about yourself and your passion. It's been almost 2 months and I haven't heard back from them. but to be honest the interviewer told me that this will take time and I have to be patient

Applied in person and was interviewed. I was asked to apply online and I did but I got a rejection. I called to follow up and ask why I got rejection but the HR won't answer my calls.