This is a very loaded, technically inaccurate statement. This recent article explains the situation better: https://balkaninsight.com/2021/11/23/kosovo-to-end-free-ener...
"Serb consumers in the four northern municipalities have not paid for their electricity since 1999. According to Radio Free Europe, the total cost of the energy used in the Serb-majority municipalities is around 12 million euros per year."
Whoever really believes that people who haven't paid their bills since 1999 would magically start paying in 2022 is quite naive.
That belief is irrelevant. It's completely different to the article's statement that the population refuses to pay it, when a mechanism for them to pay it has not existed since 1999.