Originally Published: 28 MAY 19 07:57 ET

By Rob Picheta, CNN

(CNN) -- Fans of the Spice Girls are demanding refunds after the girl group's long-anticipated reunion tour was plagued by sound problems for the second consecutive night.

Several attendees complained they struggled to hear the British band during their performance at the Principality Stadium in Cardiff, Wales, on Monday night, with some saying the problems ruined the experience.

"Amazing show from @spicegirls but the sound was terrible! Can barely hear vocals!" a concert-goer wrote on Twitter on Monday evening.

"Those in charge of sound need to improve. You couldn't hear a word when they were talking," another added, while a third said the sound at the gig was "bloody awful."

The tour marks the first performances by the 90s act for nine years, and both venues the group have played have been packed with fans.

But the event is quickly becoming overshadowed by technical issues -- the band were hit by similar audio problems during their previous concert in Dublin on Friday, which had kicked off their comeback tour.

Cardiff resident Claire White said on Twitter she left Monday's show after around half an hour, saying she was "feeling extremely disappointed with the Spice Girls." Others added they were seeking refunds, while some also questioned why the stadium's retractable roof was left open despite rain falling on the crowd.

However, many fans said they did not experience any sound issues from their positions, and others said the problem wasn't bad enough to impact their evening.

"Yes there were some sound problems, but the atmosphere on the floor was amazing even despite that and the rain," Natalie Ross wrote. "My friends and I had an amazing time."

Emma "Baby Spice" Bunton, Geri "Ginger Spice" Halliwell Horner, Melanie "Sporty Spice" Chisholm and Melanie "Scary Spice" Brown have performed the band's biggest hits on the tour, including "Spice Up Your Life," "2 Become 1" and "Wannabe."

The group achieved worldwide popularity in the 1990s before disbanding in 2000. They have reunited on two occasions, with their last tour coming in 2008.

Victoria Beckham, or "Posh Spice," is not present on the latest reunion; she performed with the band for the last time when they sang at the closing ceremony of the 2012 Summer Olympics in London.