How to get my bitcoin payment confirmed? I have invested some bitcoins on a website.
They have made a payment to me of 0.002 bitcoins to my BTC wallet, but it is unconfirmed for more than 24 hours now.

Is it due to low mining fees is given from the sending party?
What can I do about this?
Unfortunately there is not much you can do yourself, other than contacting the sending party or simply waiting a bit longer. It is, as you suspect, most likely due to low transaction fees. 
For more information you can take a look at this similar question (which is from a senders perspective): 
Why is my transaction not getting confirmed and what can I do about it?