Than is a conjunction, used to show comparison.
“She is older than I am.”
“I stayed out later than I would have liked to.”
Then indicates the next thing to come in a series.
“We went to a movie and then dinner.”
“We got to the beach and then it started raining.”
Even though some may pronounce these words the same way, rest assured they are indeed different and should be used with care.
I’ll probably never get invited to this bazaar again…