According to Heat, Nicola Roberts, Sarah Harding and Kimberley Walsh ignored Coyle's arrival in London when she visited the city to finish off work on her upcoming solo album.
A source said: "Nadine wanted to meet up with the other girls. But they all said they were too busy. Nadine was feeling frustrated, as she felt she hadn't actually fallen out with them.
"Nadine thinks she's been too patient, letting herself be sidelined. She refused to record solo material years ago, because she said she'd feel bad about leaving the girls in the lurch. She had loads of offers, but turned them down, which she now regrets."
However, another source supposedly close to the rest of the group told the publication: "They weren't leaving her out.
"There are only so many times you can invite someone and not have them turn up before you stop asking them to come along. They're not a bunch of bitches."
