@MrCookieBell (29 July, 2016, 3:45 PM UTC):
While he may have had weaker troops, he may have also had many more, closing the power difference and therefore causing you to lose more.

It also depends what you sent, since filling a HARBINGER's capacity increases the total offence to much greater amounts than the HARBINGER alone.

If you still believe that you lost units when you weren't supposed to (Bugs, glitches, etc.), you will need to contact the Help and Support Desk with information including (But not limited to) your coordinates, when the battle took place, and screenshots of such.