Complaints about cellphone and broadband contracts and online event purchases were the big-ticket items for the Commerce Commission last year.
Of the almost 9000 consumer complaints the consumer watchdog received over the past 12 months, 727 were related to telecoms, with complaints ranging from inaccurate billing or fees, or contracts that weren't agreed to.
There were also 585 complaints about online ticket selling - many from online resellers such as Viagogo and Magan - which were up nearly 63% from 2017, with complaints about offered prices not matching the charged price.
Based on an "unprecedented" number of complaints against Viagogo, commission chairperson Anna Rawlings confirmed it had now taken legal action against the Swiss-based company.
Consumers also weren't particularly happy with domestic appliance retailers, who were the subject of 469 complaints, up 78.
"Complaint themes included that consumers were told the Consumer Guarantees Act did not apply when they attempted to return a faulty product, or that they would have to pay for a repair because the manufacturer’s warranty had expired," Ms Rawlings said.
Kiwis also raised their voices about irresponsible lending, with a 40% increase in overall complaints to 116, ranging from accusations that lenders weren't checking affordability of repayments, or that borrowers were often offered more credit despite difficulties in serving current debts.
Debt collection practices also generated 124 complaints, with complainants saying they felt "unfairly pursued" or harassed.
Ms Rawlings said while not all complaints could be fully investigated she urged people to "complain more".
“We can only investigate what is causing the most harm to New Zealanders and complaints help us prioritise.
"They also show us where consumers and businesses need more information to understand or comply with the law.
"Complaints also inform the advice we give to policy makers, so our message to consumers is that we want to hear from them and we value what they tell us."