REUTERS/Andrea Comas
A policeman reacts as a woman shouts inside a Bankia bank branch during an anti-eviction protest in Madrid, June 1, 2012.
It's the pay day before a three-day weekend so they're understandably furious.
The bank said on Twitter two hours ago that it's "working hard to rectify the issue some customers are experiencing with expected payments today." There's an issue affecting the BACS payment system, according to the bank.
A Bank of England spokesperson said the regulator was "in contact with HSBC."
Customers are venting their frustration at the bank's social media accounts:
@HSBC_UK_Help This is ridiculous!!! Its bank holiday weekend. and I have plans .. Plus my Debit Orders are are due? Have you been hacked?
- Melanie Hammond (@mad_mel77) August 28, 2015@HSBC_UK_Help All we want to know is when we will receive our money, due to rent/mortgages and any DD's expected to go out this weekend!
- Nathan McDonald (@_NJM19) August 28, 2015@HSBC_UK_Help i need to pay my deposit for my University accommodation.. and the deadline is today, please can you get this sorted today?
- Husss (@Husnankazmi) August 28, 2015@HSBC_UK_Help what are the timescales for this?? Please give some answers! This is not acceptable!
- Nadia Rafique (@nadia_rafique) August 28, 2015