Bodyshop network ABS – in the process of finalising its £1.7m sale to insurance claims group Aquilo – has responded angrily to a move by estimating systems specialist Audatex to bypass what it says it a longstanding group buying arrangement and increase prices for the 240 independent repairers on its membership.

ABS describes Audatex's decision as "high-handed", but admits that the agreement with Audatex has never existed in formal contract terms. It says that for several years Audatex has allowed all ABS repairers to access a discount on use of the system that the majority, especially low-volume estimate users, could not obtain individually.

Earlier this year, with the arrival of its new web-based AudaEnterprise product, Audatex served notice that all ABS repairers adopting the latest system would fall outside of the group buying agreement from December 31, 2004 – but negotiations have been ongoing between the two companies for the roughly two-thirds of ABS repairers still using the older AudaWorkstation system to retain the benefits of the group buying arrangement.

However, Audatex has written to all ABS repairers stating that the group arrangement would be terminated at the end of this year - prompting a heated response.

Alan Hodgkinson, chief executive of ABS, says: "This is exceptionally high handed behaviour by Audatex. We have been in negotiations with them regarding this matter for a while, meeting as recently as late November, to attempt to retain the group buying arrangement for as many of our members as possible for as long as possible, which we had verbally agreed would be at least until February of next year.

This extra time would allow repairers who had not already done so to make a decision about their Audatex use.

"Without serving any notice of their intent to us at all, Audatex has now written to all our repairers withdrawing the benefit and increasing the charges with almost immediate effect.

We are angry and so are our repairers. It has unnecessarily created a lot of bad feeling and, we believe, will backfire by slowing the adoption of AudaEnterprise simply because it has created an anti-Audatex mood among many ABS members."

Audatex declined to comment on the issue: "We have a policy of not commenting on commercial arrangements," a spokesman said.