CALL CENTRE AGENTS PUT DOWN PHONE ON ME

I have just had a very unpleasant incident with this number ********** and it is totally unacceptable. What is very frustrating is that when you call it back - no one answers so you are unable to complain. The indian sounding lady told me I had been selected for a phone and she was representing MTN and was offering me a samsung phone. I politely had listened to this point and then when she mentioned the phone I then said no thank you i..... and she put the phone down on me. THIS IS WHY CALL CENTRES get a bad name. I would like it to be looked into and the consultant and phone call to be listended back on. ATROCIOUS! I dont even have an MTN NUMBER! if they were wanting my business it sure not going to happen now. :( :( :(