The East Kilbride-based company is frustrated at being powerless to counter the warning email, originating in the US and referring to TPL as being based in "Glasgow, England", which was sent to its major customer this month by business information giant Dun & Bradstreet (D & B).
Bob Taylor, chairman and managing director of the 40-year-old family business which turns over £3 million and has 500 industrial customers, obtained from Dun & Bradstreet's UK office an admission that there appeared to be "no unfavourable data" to trigger the alert which had been "generated by a US solution".
But despite promises to investigate and report back, D&B has been unable to explain the alert or to respond to TPL's request for a retraction.
Mr Taylor said: "What I am concerned about is who else has received this and what damage it could be doing to my business."
D&B initially told The Herald last week that the alert appeared to have come from D&B Credi-bility Corporation, "an entity which D&B sold some years ago".
However D&B's New York office has now assumed responsibility for the alert, and is standing by it.
TPL has reassured its major customer that it has "glowing" credit references from all other sources.
A report by Riskdisk, for instance, using company-specific information, concludes it is "a very good credit risk".
But a D&B spokeswoman said: "If there is another company supplying rates different than ours we cannot control what criteria they are using."
She added: "If the company wants to see a copy of their report we would be more than happy to send them a copy."
A company could update or challenge items in the report using a form provided.
The alert related to TPL's score on D & B's SSI (supplier stability indicator) system, raising it from four to six.
The SSI uses four areas of data – payment experience, public record items, financial statement information and demographic data covering "the location, line of business, age of business and employee counts".
The TPL alert specified only two factors: "number of employees suggests higher risk" and "higher risk country based on failure rates".
Stuart MacKinnon, senior public affairs adviser for the Federation of Small Businesses in Scotland, said: "It is difficult to know what causes these alerts, whether it is necessarily the characteristics of the business in question, or whether it is the range of data they put together in these reports."
The FSB understood the trade body British Information Providers Assocation was studying "ways of making their systems more responsive".
Mark Hargreaves of Experian, chairman of Bipa, was unavailable for comment.
Mr Taylor said: "It has taken 40 years to get this business to where it is today, and in theory D&B could destroy that in an instant with false information."