why would a guy avoid me?

this guy works at this deli shop at the register/answering phones. he has always waited on me family members of mine even told him how we already ordered and he wouldn't respond just ring us up cause I said he always does this...to me. I never saw him do it for others. I called he answered said ill see you soon. also I feel like he had a smile on his like sometimes you can tell someone is smiling over the phone and I feel like he was. I went picked it up he handed me it in a bag with both hands said have a good day hun. he never called anyone else that. he looked up saw me looked down back up again then went back to work. I went in with my brother twice and he stopped acting this way...ever since then he would see me and turn around walk into the back of the store or like try to avoid me...why? should I just move on? I think hes cute and have since the first day I saw him at work. people say its his job but it doesn't make sense why he stopped right after me and my brother went in. I also am shy...and don't know what I should do if I should make a move or leave it alone..
I went in on Halloween and he was working. he looked at the door saw me...looked towards the back of the store and kept looking back between me and the back. he asked me what I wanted then said have a good day