When it comes to marriage, you have the right to decide whom you want to marry. So, if you have reasons to believe that the person who proposed to you and his family are overly materialistic, then you are justified in rejecting the proposal. It does not matter that they changed their minds afterward. If your first impression of them was not very pleasant, that is enough reason for you to reject the proposal.
The Prophet (peace be upon him) had set out the criteria for choosing marriage partners when he said, “People marry for reasons of wealth, status, beauty, and for religion; you may do well to hold firmly to religious factor!”. (Reported by Bukhari).
He also said, “When someone of sound faith and character comes forward marry him; otherwise, you are paving the way for corruption.” (Reported by Tirmidhi).
I pray to Allah to bless you with a righteous partner to build a happy family.