Are you sure that Sri Lanka's Bank of Ceylon banned bitcoin? I'm looking for an article that has this news but the results are poor.
This is one of their latest statement: April 16,2018.
Public Awareness on Virtual Currencies in Sri LankaThey are giving warning to their people but there's no ban.
I red the same article but it doesn't clearly mentioned about bitcoin banning it is like an announcement to warn people about digital currency usage in locally but nothing is mentioned about the government or the central bank is going to ban cryptocurrencies in Sri Lanka but many rumors are coming that government is against the crypto use so only the time will tell what is going to happen but better to stay alert