The Charles Church group reported revenues falling 4.5% to £1.75 billion for the six months to June 30.
It delivered fewer homes - 7,584 for the six months to June 30 compared with 8,072 a year earlier - as it slowed down construction.
Forward sales also slowed to £1.6 billion, down from £1.7 billion a year ago.
Average selling prices rose 0.5% to £216,950, with private sales rising to around £238,350 from £236,700 a year earlier.
The group said its “top priority is to deliver continued improvement in its service to customers”.
“To help achieve this we are adopting a more targeted approach to the timing of new home sales releases on certain sites and plots where demand is particularly strong,” it said.
The group said average active sites reduced by 8% in the first half.
York-based Persimmon has recently faced a barrage of criticism over build quality.
It scored the worst figures of all the major house-builders in a recent Home Builders Federation new homes survey.
The firm launched a review of its house quality and customer care functions in April.
Persimmon chief executive Dave Jenkinson said: “I am pleased that there are some clear early signs that our focus on increasing the quality and service delivered to our customers is beginning to bear fruit, with some encouraging improvements being made right across the business.
“Our progress on customer service shows that Persimmon is listening carefully to all stakeholders and making the changes needed to position the business for the future, while maintaining a robust trading performance.”
Persimmon, which reports first-half results on August 20, saw shares edge 1% lower after the update.
As well as customer services woes, the group also faced an investor revolt last year after paying big bonuses to senior executives and enjoying a substantial rise in profit on the back of the Government’s Help To Buy scheme.
Former chief executive Jeff Fairburn faced particular criticism after refusing to answer questions over his own proposed £110 million bonus package.
He was eventually awarded £85 million over two years.