Replacement of notebook

I went to the computer shop in Greentown to exchange my notebook yesterday. They show me the newly exchange notebook and explain it to me.

I query them why they changed my notebook RAM silently. I request them to give me an explanation. The only reason they gave is "It's technical departments mistake!".

I knew it would not do me any good quarreling with them, so I took my notebook home. I will make a complain to HP.

Nowadays, we need to be much more careful in purchasing, not to give any chances for others to cheat.