Almost half-way the first through term, some 6000 students at Scottish universities have yet to receive payments for living expenses such as rent and food.
The Students Awards Agency for Scotland (SAAS), which distributes the money, does not believe it has breached any of its guidelines, with the rest of the 150,000 applications already dealt with.
SAAS has a target to provide payments to all students who apply before the start of July and the organisation has told student leaders it has met this commitment.
However, some students disagree saying they applied before the deadline and still have not received any money.
Many students who applied after the deadline – either because they were late or because they secured a university place in the final weeks of clearing – also have not yet received payment.
Student leaders have now called for an inquiry into why so many bursaries and loans have not been distributed.
Robin Parker, president of National Union of Students Scotland, said the agency’s staff were working hard in difficult circumstances.
But he added: “The Scottish Government needs to investigate why students will still be waiting for their support payments in November, and look very closely at providing the additional resources SAAS would need to process applications quicker.
“Students who have not received support funding have every right to be upset, and are absolutely right to expect a better level of service.
“Many students rely on this funding to afford their education, and could struggle to remain at university without this much-needed support.”
The Scottish Government said on Wednesday morning that 7572 applications had yet to be processed by SAAS, but later updated the waiting list total to 6000.
It said it had invested in new technology to make the SAAS system more efficient and believed anyone who applied by the end of June would have received payment.
Dominic Smith, a physics student at Glasgow University, said: “I applied a few weeks after I finished my exams in May. It’s almost November but money still isn’t through. I’m using a bank overdraft to pay for things like food.
“When you phone up you go through this system then get put on hold for what can be up to 40 minutes or not get through at all. I’m even paying for that call with my overdraft.”
Craig Angus, vice president media and communications of the university’s Student Representative Council, said: “It seems to be chaos. We know of 15 students who have been asked to resend their proof of income because it seems to have been mislaid. We suspect there are many more cases.
“It is so frustrating because students can’t even get through on the phone to find out what is happening.”
He added that because applications were stuck in the SAAS system, students often had no proof they have had no payment, so they may struggle to access emergency welfare pay-outs from universities.
SAAS has revealed it is receiving up to 1000 calls a day from students among the 151,000 original applicants.
In a letter to universities, it also revealed it is so overwhelmed with calls, two weeks ago it started closing the phone lines entirely one day a week.
A Scottish Government spokesman said this would allow it to spend more time dealing with applications and mail.
“SAAS is committed to ensuring students get the information and help they need - and of course their applications processed as fast as possible. Clearly there are intense periods of calls before and at the start of term time,” he said.
“New applications and changes to courses, attendance and other elements of the students support package continue to be received on a daily basis and are being processed as quickly as possible.”