Gst on export of service

A Indian company exports it's machinery to a foreign company on the terms of 2 year warranty period. After 6months of export there were some technical issues found and a Indian company employee personally went to resolve the issue. Following are the situation
1. Indian company bears the whole expenditure and no amount is recover from the foreign company.
2. Indian company recovering the whole computing amount from the foreign company.
How to deal with these situations and what are the disclosure required in gstr-1 and gstr-3b returns.