Homebuyers have been chased by the taxman and threatened with debt collectors because the country’s largest conveyancer failed to pay their stamp duty on time.

Clients of Simplify Group have received letters from HM Revenue & Customs demanding payment of outstanding tax for purchases that completed months ago.

Conveyancers usually pay the stamp duty bill on the day of completion, using funds transferred in advance by the buyer. The tax is due no later than two weeks after the purchase. But clients of Simplify have been left in limbo after the firm missed deadlines.

Stephen Parsons* completed a purchase in the East Midlands in December and assumed his £3,500 stamp duty bill had been settled as promised by Premier Property Lawyers, a subsidiary of Simplify. He said: “I was somewhat alarmed to move into the house in early January to find a letter from HMRC demanding the stamp duty.”

Payment up to three months late results in a £100 fine, which increases to £200 thereafter. Interest is owed on the tax bill from the day after the missed deadline and is charged at 3pc.

Mr Parsons chased his conveyancer but received another two letters from HMRC warning the tax bill had yet to be paid. The final letter, which arrived in February, warned the matter had been passed on to debt collectors.

“The tax is paid now, but it was stressful getting there. The worst part is the conveyancers didn’t even tell us they hadn’t paid it,” he added.

It is the latest in a series of failings at Simplify. In November it was hit by a cyber outage which halted exchanges and completions and put thousands of home sales in limbo.

However, the trouble began long before that. Customers have previously told Telegraph Money of months spent chasing lawyers for an update on transactions, only to be ignored, given false promises or for sales to fall through. 

After months of waiting, clients have now been hit with final bills from the company asking for thousands of pounds more than originally quoted.

One Simplify customer, who wished to remain anonymous, was given an original estimate of around £900 to cover conveyancing fees. But the final bill she received totalled more than £4,000.

A spokesman for the company said: “In the early stages of the [cyber outage] incident, there were some delays on payments and transactions as we found solutions to restore our systems safely and enable clients to move.

“The delay included some stamp duty payments. All money held by Simplify is in an entirely separate system and was unaffected by the incident.”

It added: “Stamp duty payments are now being processed as normal, but if any of our clients or partners have received a query from HMRC regarding a payment they should contact us immediately.”

A Simplify spokesman said the company also detailed all “known charges” and “any potentially additional fees” in initial quotes to clients. The firm said “where additional fees need to be applied for specific work these are notified to the client”.