I also couldn't find any official info on ACTUAL PAYMENTS. Only some tweets and articles in the mass media, which is frankly not a very reliable source.
This is a tweet of Maduro himself, showing also part of his speech of April 26:
https://twitter.com/twitter/statuses/989958118661640192In the speach he affirms that "3,338 billion dollars have entered". ("Han ingresado 3 mil 338 millones de dolares.")
Later on he explains that "we made transactions to import worth 1,738 billion dollars" and "1,6 billion dollars cash, cash, in various currencies, in ready money then."
Of these 1,6 billion dollars he decided to give 1 billion to the central bank to increase the international reserves "immediately, tomorrow at the first hour":
"De estos mil 600 millones de dólares he decidido entregarle al Banco Central de Venezuela para la reservas internacionales, aumentar las reservas internacionales de Venezuela y fortalecer el Dicom de inmediato, mañana a primera hora, mil millones de dólares al Banco Central de Venezuela para jugar con la subasta del Dicom".
I don't know how he could give 1 billion dollars to the central bank the next day if Venezuela hadn't received this money in actual payments.
You can watch the full speech at:
https://www.pscp.tv/w/1MYxNpykLPpGw(Of course I don't claim that anything of what Maduro is saying is true. I just want to point out that the official "information" is, that foreign currency worth 3,338 billion dollars acutally entered the country.)