I should have been pleased when the cheque arrived from our local health trust. After two years, we'd won our complaint against them and received compensation. But I wasn't celebrating. The process was time-consuming, costly and may mean my daughter is refused future treatment. The price of our victory is simply too high.

Last week, health service ombudsman Ann Abraham said the NHS complaints system was continuing to fail patients. She warned of the need to thoroughly investigate complaints and called for trusts to learn from the process. The sad story of our complaint demonstrates this need all too well.

It began in December 2002, when my daughter's community therapist said she needed a new wheelchair. When the wheelchair service gave her an appointment six months later, they prescribed a chair that was so heavy that she would suffer extreme fatigue, wouldn't be able to self-propel, and would lose her independence. It was also very cheap.

At first, we tried to negotiate. But the wheelchair service's response was to become even more entrenched. We had no choice but to make a formal complaint on the grounds that the wheelchair they prescribed didn't meet our daughter's clinical needs.

Immediately, we were treated as the enemy. We were seen as an awkward, lippy family wanting more than we were entitled to.

Six weeks later, the trust's chief executive wrote, "the concerns you raised have been investigated". This "investigation" only involved talking to the wheelchair service - the same people against whom the complaint was made. There had been no contact with us or the community therapists. An independent assessment was refused. Our complaint was dismissed.

We wrote back immediately requesting an independent review. The trust responded that it wanted a second clinical opinion, taken from our daughter's medical notes, to which we agreed. That opinion declared its choice of chair clinically inadequate, and said a full independent assessment should be offered.

Ten months later we were finally given one. The assessor's report unreservedly supported us. The trust's chief executive sent us a short, upbeat letter saying he was "pleased that a satisfactory conclusion has been reached" and a cheque was in the post.

But last week I received another phone call from the same director of therapies who'd summarily dismissed our complaint 18 months earlier. My daughter needs a new specialist cushion for her chair. But the cushion is provided by the wheelchair service, and the director was phoning to let me know they had "difficulty" working with my daughter. The trust was refusing my daughter treatment because we'd won a complaint against it. If we wanted treatment, we had to prove our willingness to comply by agreeing to yet another meeting.

But we've had enough meetings, written enough letters, and made enough phone calls. We have, as I reminded the director of therapies, also been vindicated by two independent assessors. Then she delivered the final blow: the wheelchair service still stands by its original decision. According to them, the judgment of two independent assessors means nothing. Now our main fear is, as my daughter grows and needs a larger wheelchair, we'll have to go through the whole procedure again.

Last week's ombudsman's report states that healthcare providers are failing to learn from their mistakes. My local trust has learned nothing. Instead, it's chosen to simply wait for the next persistent family with a grievance to come along. And when that happens, the trust will only be interested in defeating them, just as it was only interested in defeating us.

It didn't. But that doesn't make me glad. Because, despite the independent assessors finding in our favour and the cheque, no one has won.