Maybe replacing ailing frontman Brian Johnson with Axl Rose wasn’t such a great idea for AC/DC.

Billboard reports that thousands of fans in Belgium and Spain have requested ticket refunds for upcoming dates on the band’s European tour.

An unnamed source tells the magazine that there was “a bit of drama” surrounding the substitution of frontmen resulting in the refund requests.  But, the source says, there were also a significant number of new ticket buyers. Tour personnel “aren’t worried about it,” the source is quoted as saying.

News of the refund requests first surfaced earlier this week in Beligian newspaper De Standaard.

Last month, AC/DC postponed 10 shows in the U.S. after Johnson announced that he was struggling with hearing issues and would be forced to stop touring, AC/DC announced plans to complete the European dates on its Rock or Bust tour with the Guns N’ Roses singer subbing for Johnson.