According to an inquiry made to Sri Lankan airlines customer service in March 2016 posted here
Thank you for contacting SriLankan Airlines.
Refer below criteria to be met in order to be eligible for complimentary >transit hotel accommodation as requested.
We regret to inform you that we do not handle visa queries. Please visit >www.eta.gov.lk for more information if required.
- The transit time should be over 8 hours and less than 24 hours.
- The net fare paid should be over USD 180(exclusive of taxes) for one->way journeys and over USD 360(exclusive of taxes) for return tickets.
- The connecting flight must be on the first available connection.
- Pakistani passport Holders should obtain ETA.
- Hotel accommodation will only be provided in Colombo.
If you require further clarification, please contact our Call Center on >the numbers below.
Within Sri Lanka – 1979 | From UK - 330 808 0800 | From Singapore - 315 >805 80 | From Germany - 6990 732 333 | From France - 9751 81999 | From >Hong Kong - 819 800 79 | From Japan – 505 532 3229 | From Italy – 0689 >970 268 | From Malaysia – 321 683 615 | From Thailand – 600 035 642 | >From outside Sri Lanka - +94 11777 1979
According to other posts in the same thread they can help with the visa, however they recommend doing it online as it is a relatively fast and easy process.