The MtGox Bitcoin exchange, which last week sought bankruptcy protection in Japan, opened a helpline for anxious customers on Monday after unveiling a massive loss in a possible theft.
The troubled exchange filed for protection with the Tokyo District Court Friday, admitting that it had lost nearly half a billion dollars worth of the digital currency.
The call centre will respond to "all inquiries to MtGox", the Tokyo-based firm said on its website. "An overview of the situation should be published here shortly."
A company lawyer said 750,000 Bitcoins belonging to customers had gone missing, along with MtGox's own store of the currency, which she said was around 100,000 units.
That number of Bitcoins would be worth around $477 million, calculated against the price on the Coindesk exchange at 0300 GMT on Monday.
MtGox CEO Mark Karpeles, who had not been seen in public for several days, re-emerged at a news conference on Friday to reveal the extent of the disaster and apologise to clients.
The global virtual currency community was shaken last week by the shuttering of MtGox, which had frozen withdrawals in early February because of what the firm said was a bug in the software underpinning Bitcoin that allowed hackers to pilfer them.
Supporters rallied round, insisting that the Bitcoin itself is sound and the problems lay with MtGox, which they said was badly managed and unable to cope with the burgeoning popularity of the young currency.
In the announcement on its website, which appeared in Japanese and English, MtGox said the telephone number of the call centre is +81-3-4588-3921. It will be open weekdays from 0100 GMT to 0800 GMT.