Crossed wavelength frequencies

I was trying to call my mum and it came up an 0033 number on her phone. Then after I tried calling my sister, the first few times it didn’t work, it never rang the third then when the call counter started, it crackled a few times then a funny voice came on the line. At first I was generally worried then I realised it was a different accent on the line, I listened for a few mins then recorded about 20-30 second clip. It was really strange, is it possible to have maybe cellular network had gotten crossed somewhat and picked up a international line?