The organisation claimed that businesses have been unable to file challenges on the website, launched last month, due to “limited volume” which is causing the system to crash.
The VOA website is the platform for businesses to start an appeal under the new business rates regulations.
CVS, which assisted with the testing of the system before its launch, claims it had previously warned that the system was "buggy, unstable and missing vital features".
Industry bodies have also slammed the website, with the Association of Licensed Multiple Retailers (ALMR) describing it as “unintuitive, unfit for purpose, long-winded and difficult to use”.
Poor on functionality
Mark Rigby, chief executive of CVS, said the website has “really poor on functionality”.
“If deterring appeals was the ultimate goal, a better platform could not have been devised,” he said.
“Alternative arrangements must now be made so all businesses that have registered their properties and are represented by a professional advisor can move to challenge their new assessment rather than simply sitting, waiting for IT issues to be resolved."
It is understood around 4,000 businesses have managed to register in the first month, said the CVS.
Calls for action
The British Beer & Pub Association (BBPA) said it is “monitoring the situation” and has urged the officiating bodies to take action.
“We have also been receiving feedback from members that online registration is very cumbersome, and the site has been crashing,” said chief executive Brigid Simmonds.
“This needs to be resolved as soon as possible, and we are looking to discuss these issues with the VOA as soon as the election ‘purdah’ period is over.”
The Association of Licensed Multiple Operators (ALMR) said it had warned that the Government needed a robust and transparent appeals system in place.
“Plainly, this system does not work and is wasting the time of employers who could put their time to much better use than covering up mistakes in a completely out-of-date and unfair system”, said Kate Nicholls, ALMR chief executive.
“The current rates system is partly predicated on having a responsive appeals system that works for businesses and guarantees a modicum of fairness.
“The Government needs to make sure its appeals system is up and running and that employers have the ability to challenge any mistakes.”
A VOA spokesman said: “The new online check and challenge service is working normally.
"Anyone requiring help to register with the new service should follow the step-by-step guidance.
"We value feedback, and review our online service based on what users tell us."