Yes, it's unfair, and you will have to make peace with that. All businesses suffer losses from factors beyond their control. It's an expense/cogs line item just like your hosting bill. Be glad you don't share the plight of retail stores: not only do they get credit card chargebacks too, and are vulnerable to types of payment fraud you're not, but 1 in 11 people walking around have shoplifted at least once. 1.5% or more of the average retailer's inventory will simply vanish as shrinkage to theft, damage or lost items each year.
In your specific scenario, you likely didn't have the evidence needed to rebut those chargebacks. The only time you can rebut reason code 41 (cancelled recurring transaction) is if you have evidence the customer "did not cancel the transaction". A customer sending you nothing (i.e. subscribed, paid a few months, never requested cancellation) means you have no such evidence that they did not cancel those specific renewals. The customer, on the other hand, "does not have to supply evidence that you received a cancellation notice".
If these are losses you can work into your margins, then just walk away from these chargebacks. Unless these transactions are thousands of dollars each, it's probably not worth the time and energy pursuing the unpaid bills instead of operating the business.
