The Salvation Army is under investigation after thousands of pounds worth of bills were left unpaid and finances left in 'a massive mess' due to an accounting system error.
A Charity Commission probe has been launched after the Christian group reported the problems to the watchdog.
Staff were left in 'despair' by the failures as they received final demand letters and warnings because the unpaid bills were in their names, a source told the Mail on Sunday.
The paper said the chaos was caused by an accounting system called SAASY introduced in April to centralise the charity's finances.
Christian Today has approached the Salvation Army for comment.
A Charity Commission spokesman said: 'It is up to charity trustees to make considered administrative decisions that are in the best interests of their charity. The Salvation Army has reported a serious incident to us regarding problems with a new accounting system. We will assess the information to determine whether regulatory advice or other action from the Commission is required.'
A source told the Mail on Sunday: 'We've had hundreds of court demands and final pay demands.'
They added: 'Red letters are arriving every day. The officers are being pushed to the edge by the sheer stress of the situation. Some are so fed up with the financial pressure they are being put under that they even are thinking about leaving the Salvation Army. It is completely out of hand, an utter shambles and just one massive mess.'
The paper also quoted an email to staff sent from trustee Lieutenant-Colonel Alan Read which said: 'I am horrified to learn of the difficulties many of you have encountered during these long weeks and despite the distress and anxiety this has caused and the depths of despair some of you have plumbed, you have continued your mission work.
'I applaud you and say that it is against the difficult backdrop of SAASY that you have continued working. Sorry will never be a big enough word.'
The Salvation Army said in a statement last month: 'We want to take this opportunity to unreservedly apologise for the delay in some of our suppliers receiving payment for invoices and the added pressure this has had on some of our officers and staff.
'We recognise that as we strive for stringent accounting processes across the country, there have been issues that have slowed us down, but we remain committed to accountability and fair business and we want to reassure people that we are taking all actions necessary, to ensure smooth operations going forward.
'Big changes do take time but in the long term we know that the new system will improve our efficiency of operations, particularly for our officers, staff and volunteers who work to serve on the front line in their communities. In the meanwhile our teams are fully committed to working through the challenges of implementing this new accounting system as swiftly as possible. We'd like to thank everyone for their patience and understanding.'