You shouldn't spend the fund that comes from an unconfirmed transaction.
You should use a wallet which supports coin control, so that you can choose which coin you want to be used for your transaction.
I actually am not aware if the funds I sent in that txn was unconfirmed. I'll take a note of this in my future transactions.
I will also be researching which wallet I can use with the coin control as you've said. Thank you.
I just realized that mempool makes a sound whenever a transaction that has just been confirmed is opened in your device.
It did. I received the notification as well.
Now @OP don't need to worry anymore if he not received his 0.3 BTC.
It's actually just 0.013 btc lol. I wish I have 0.3