Unhappy consumers kept the Credit Ombudsman Service busy over the past year. Complaints to COSL increased by 37 per cent in the year to June, and inquiries were up by 30 per cent.Once again, the big issue was how credit providers handled customers in financial hardship. Complaints relating to hardship made up 32 per cent of the 3763 complaints COSL received.In most of these cases the consumer's complaint was that the lender would not agree to a payment variation on the grounds of financial hardship.Debt collectors attracted the most complaints. COSL received 237 complaints about Credit Corp Collections, 219 complaints about the ACM Group, and 130 about Baycorp Collections.Among lenders, Advantedge Financial Services (owned by National Australia Bank) stood out, with 109 complaints. Non-conforming lenders also appear to have difficult relationships with their customers. Pepper Australia had 82 complaints made against it, while Bluestone Equity Release and Bluestone Mortgages had 42 complaints between them.And the motor vehicle finance provider BMW Australia Finance had 59 complaints.Personal loans were the products that most often gave rise to complaints, accounting for 66.2 per cent of complaints. COSL increased its staff numbers by 40 per cent to handle the workload. It took the ombudsman an average of 69 days to close a complaint, compared with 77 days in 2011/12.Seventy-five per cent of the complaints closed in 2012/13 (which were within COSL's jurisdiction) were resolved by agreement between the parties.Apart from complaints about hardship applications, other common complaints related to fees and the appropriateness of the finance (this was the most common complaint made against brokers).There was also a significant number of complaints about incorrect payment transfers, unauthorised transactions on debit or credit cards, and incorrect listings on credit files.Some of the systemic issues that COSL identified included brokers promoting over-valued investment properties and lenders adding extra fees to loan contracts.