Two owners of a seafood restaurant in Bangkok have been sentenced to 1,446 years in prison each by a court in Thailand for defrauding the public.

Last year, Apichart (Jome) Paronjullaka and Prapassorn Bovornbancha, co-owners of Laemgate seafood restaurant launched an online food promotion that required customers to pay in advance. Up to 20,000 people purchased 50 million Thai baht (£1.2m; $1.6m) worth of vouchers, said broadcaster Thai PBS.

One such deal offered a seafood meal at 880 baht (£22; $28) for 10 people – far cheaper than their usual prices.

But by March, the company – Laemgate Infinite – announced its closure, claiming that it could not get hold of enough seafood to meet the demand. It offered to refund customers who had bought vouchers, according to Thai PBS. About 375 out of 818 customers who complained got their money back.

Bowornbancharak and Bowornbancha were arrested after hundreds of people filed complaints against the company and its co-owners.