Did I gave my number to him??

okay so Im at the library with my friend chatting about guys when all the sudden these 2 guys come up to us and start making conversation. They were both cute I didnt know which one to look at. Time was running out and they took our books and walked us to cl. oh and they are both cousins by the way. Anyways the one that was walking me was starting to attract me in a good way. As we arrived to the cl room they both asked for our numbers we didnt trade.. The guy that was walking with me asked and i gave hime my number. He said " Ill call later on so you can save my number". All of the sudden as the day progresses I recieve a tex saying whats up. I reply saying who is this and the tex said it was the one that sang for you....I was shocked I mean how can he have my number i didnt give it to him. later on he said that they were both interested in me.. but why does he have my number? I wanted the other guy that i gave my number to tex =[ why did this happen>? I didnt give him my number. help