Unconfirmed transaction for 17 days https://blockchain.info/tx/e50d760324d5ef982f8566a0a3cd9e1233c8b77aeea53ee72af77c12328b1374

I sent this transaction 17 days ago through the Blockchain Online Wallet and it's still unconfirmed.

I tried ViaBTC accelerator but it always says "Submission are beyond limit."
I've also read about some other solutions but they seem very technically complex and potentially dangerous if you don't know what you're doing.

Please help.
Research how to construct replace by fee transactions. E.g. Samurai wallet has it integrated.  Or wait for a month and your transaction will be dropped from the memory pool.