I found a free service where you can accelerate your bitcoin transactions which are stuck. Visit the following URL:
https://pool.viabtc.com/tools/txaccelerator/
Limitations:
1. Your transaction must include a minimum fee of 0.0001BTC/KB.
2. Its not instant. Once ViaBTC (mining pool) discovers a new block they will include your transaction.
3. Their service has a limit of 100 transactions/hr.
I have personally tested this service and it seems to work fine. There are no charges involved to avail this service.
https://pool.viabtc.com/tools/txaccelerator/
Limitations:
1. Your transaction must include a minimum fee of 0.0001BTC/KB.
2. Its not instant. Once ViaBTC (mining pool) discovers a new block they will include your transaction.
3. Their service has a limit of 100 transactions/hr.
I have personally tested this service and it seems to work fine. There are no charges involved to avail this service.