thank you brother for ur help, tell me what i should do and i will do it now
Follow these instructions very carefully. I am going to give you specific instructions for using Electrum to import the private keys from blockchain.info to Electrum and then have you sign a transaction to broadcast it.
First, go to your bc.i wallet and go to Settings > Security. Then click on the "Backup Phrase" button. This will have you go through a process to get your twelve word seed phrase. Copy those 12 words somewhere safe.
Then go to
https://electrum.org/#download and download and install Electrum. Once it is installed, when you first run it, it should have a dialog for creating a new wallet. Choose the "Standard wallet" option and click Next. Choose the "I already have a seed" option and click Next. In the box, enter your 12 word seed phrase. Click the "Options" button and check the box for "BIP 39 Seed". Click Next and set a password. Then click Next. You should now have an Electrum wallet which should exactly mirror your blockchain.info wallet. You should see any confirmed transactions in the History tab. To double check this is your wallet, click on Wallet > Addresses. You should get a list of addresses. Double check that they match the ones in your blockchain.info wallet (you will probably get more addresses than you have in your bc.i wallet).
If that is all correct, then now you can create a double spending transaction. Your unconfirmed transaction shouldn't appear in the history list, and if it doesn't, then you can use the send tab to send your Bitcoin to an another address in your wallet. Once the transaction is signed and broadcast, the broadcast may actually fail. In the dialog where you see the transaction details before broadcast, click the "Copy" button and then paste that into a post here. That will post your raw signed transaction for others to broadcast for you should Electrum fail to do so (because its a double spend).
If it does appear in the history list, report back here.
