The problem likely has to do with blockchain.info's poorly written wallet. They often have issues with accidental double spends and spending unconfirmed funds.
Can you please post the transaction ids of the transactions in question so that we can see what is wrong with them?
I though bitcoin was suppose to be a easy safe way to send money. Seems to me to be very very insecure.
Bitcoin itself is not insecure. The insecurity lies with wallet providers and wallet developers when they make poorly written wallets, like blockchain.info. As I said earlier, blockchain.info frequently has issues that can be extremely confusing to their users. I highly recommend that you stop using them and switch to a desktop wallet such as Electrum, Multibit, Armory, or Bitcoin Core. Any wallet listed on
https://bitcoin.org/en/choose-your-wallet is considered reputable and won't have such issues as you are facing (notice how blockchain.info is not listed on that site).