1)I got official receipts for all payments I made therefore there is no chance of a fraud here unless official receipts themselves can be forged, something which I highly doubt. Till now, no one told me I paid higher except you, and I have talked about this to alot of friends.
2)Auction numbers not contested are not carried over, at least not in mar 2010 when I paid a huge amount for my number. I am pretty sure this is still not allowed because otherwise no one would participate in auction other than for numbers like 1, 786 etc. For the rest, everyone would buy carried over numbers are peanut prices.
Just to give you an idea, I purchased 666 for more than 10 times the reserved price. There was fierce competition and apart from me, 4 more people were bidding (the scene was exactly like you see in indian movies). Same was case with other numbers like 88,888,555,999, 11 etc (these were the ones in which I participated)