Yes, you could remove the easyroam add-on but keeping the international voice and data roaming add-on.

However, the rate is astronomical high https://www.koodomobile.com/en/payperuse please check before you proceed.

The reason you were charged easyroam is that it was active on your account. Depending on what a “few minutes” of use means, and where, is it really so much smaller than the 14 or 16 dollars that easy roam cost? The only pay per use rates I’ve seen that aren’t extremely expensive, is texting in the US.

I don’t believe that you’d be able to get it retroactively removed to be charged Pay-per-use instead of easy roam. How much of a price difference  is it?