Can anyone explain why this website has missing data? I was trying to use the api that is located at:

https://api-r.bitcoinchain.com/v1/address/13gWtMQJdg3H6XBpFjMELcHLJc1HHp79vD

However, for every address I look up, they seem to be missing some transactions and subsequently have incorrect balances for each address.
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