From Wengowiki

How are my calls deducted from my Wengo's balance ?

Your credits of communication, the Wengo's, are deducted at the minute as of the first minute. The calls of less than 5 seconds are not charged.

There is no credit time, neither load of establishment of call, nor cost of connection. Wengo invoices the calls in the most transparent possible way. To learn more about the Wengo tariffs click here.

How can I rebalance my account if it turned to negative ?

Your last call has exceeded your remaining communication credits; this is why your Wengo's balance is negative.

In order to make further calls, you need to buy a new credit line and balance your account.

If you need more information, please contact Wengo Customer Service on the Forum.