Go to the page of your font. Select "Webfont" at the top.
In Firefox (only Firefox) click Shift + F7 to open the Style Editor.
Copy and paste the text from the final stylesheet on the left.
Paste that into a text editor of your choice, making sure word wrap is disabled first.
Delete the CSS links to the fonts you don't need. Leave the lines for the fonts you need.
Enable word-wrap now. Find the partial URL in the text that starts with /v2/ttf?<blahblahblah>
Paste this after the url http://easy.myfonts.net
Click Save and save it as fontname.ttf and convert it online to OTF.