You can try free accelerators such as ViaBtc. I know they have a minimum fee in order for them to accelerate it, which I can't remember now, but you can always  try the other services which have varying criteria for accelerating the transaction. ViaBTC also has a max limit of submissions each day which have probably already been used.

Here's a list of all the free and paid accelerators: https://bitcointalk.org/index.php?topic=2624419.0