SAYA or AKU

I feel so weird if in the professional or formal situation, I meet someone and then he or she describe his/her with "aku".. In Indonesian there are two words to mention yourself : "saya" and "aku", and for me "saya" is the right word to use in the term of work, job or formal conversation.

I would lost my appetite to continue the conversation, if for the first time we meet, someone called him/her self as "aku", such as : "good morning bu, aku from PT BUTUWANG, and aku would like to introduce our product bla bla bla".. or a teller said "bu, aku have transferred your money to bla bla".

And in the traditional market, some vendor call me "TANTE". Oh noooo.. argh and I'm not hesitate to answer : "mas, please just call me IBU, I'm not your TANTE".. (and I don't even know you as my nephew)