Don't ever accept an offer lower than your current unless you are desperate or out of work. The interviewer was trying to short-change you in terms of salary and position. When you spend enough time working, the BIG FOUR or MNCs are just a name that means nothing, especially when you have got the skill-sets and experience that are in demand.

Put them in Glassdoor and they will be thinking twice before doing the same to others.

Consider yourself as a consultant selling services. Are you willing to accept lower offer price than you are selling?