If she's caught using regulated credit, the IVA could fail and she could be made bankrupt.
However she shouldn't be able to access credit, I thought Klarna was being regulated, ie I know there didn't used to be a credit check and credit file entry, but I thought that had changed?
It sounds like she needs more than help with unmanageable debt, she needs treatment for the spending addiction otherwise she'll just get into debt again as soon as the IVA is over and she'll be back at square one in huge debts.
Does she want to stop overspending or does she not see a problem? Sounds like she's in a cycle that needs breaking. If she managed to not borrow extra for one month, or all the people she borrowed from said no, she wouldn't have money to pay back and she could then just live on her current income each month.
Is she a homeowner? An IVA is supposed to relieve people who own their homes from unmanageable debt, otherwise in nearly all cases they should go bankrupt (there are a very small minority of occupations that would be put at risk by bankruptcy but it's not that common and if this applied, she should seek help from her union, professional association or other employee assistant service).
But either way it's also an opportunity to learn to live within your means on a sustainable budget that allows for reasonable spending on non essentials and other annual and irregular expenses like car repairs etc. This is all set before the debt repayment is agreed so it shouldn't be necessary to borrow as long as you stick to the budget, because money is available for all needs and some wants plus repayment of debt.