Problems with whatsapp and skype on galaxy s6

[AC Question]

The thing is that I left my phone on my bag and my boyfriend decided to call me on skype and the call was sounding like when a phone does when somebody is waiting for his or her call to be answered, and my phone should have answered right away since I set up my skype to answer each videocall or normal call automatically on my phone. Besides the skype call, my boyfriend also called me on whatsapp and he said the call went on hold as if I was talking to somebody else, but as I mentioned before my phone was in my bag, so how is it possible that my phone send calls on hold while it was on my bag and I was not even looking at it? Please can somebody help me? I'm sorry my English is not so good but I did my best so that everyone can understand, I really need help cause these issues are giving me problems not only with my boyfriend, but also with my friends and family.