I know I'm going to come across as a bit of a noob here, but I'm at a loss for signing a multisig transaction and broadcasting it to the network. I have my private key from an original transaction and I'm attempting to process a refund from a vendor and sign a transaction, and then broadcast it to the network. I've used electrum, bitcoin core coinb.in and even brollet, to no avail. It seems I can sign my transaction, then when I verify it, it shows one of two signatures and when I attempt to broadcast it, it give me a tx-rejected error, presumably from the missing signature? Is there anyone that can walk me through or point me in the direction of some noob friendly formatting tips, tutorials or software that can walk help me verify, sign, verify again and then successfully broadcast a transaction on the network.  Thanks in advance!