If you go to this page after clicking on download button or SKIP AD button. See the screenshot below
The Mp3 File will run automatically and You can listen the song from this page. So the Question is How you can Download this file. Very Easy way just follow the instructions below.
For Google Chrome:
Press Ctrl+S and then Choose your location and click on Save button. See the Screenshot
Or use this way for Google Chrome. Just click on the expand icon then select Save page as.
For Mozilla Firefox:
Press Ctrl+S and then Choose your location and click on Save button. If the key not work then You can save the file from menu bar. So to do it at first you have to show the menu bar on the top of the browser. Right click on the bar and then select Menu Bar. See screenshot.