VKVinoth Kumar Sundara Moorthy Syncfusion Team September 11, 2019 05:55 AM
Thank you for contacting Syncfusion support.
We have checked your reported issue in the version (22.214.171.124) and the file imported properly in our end without any error. Also, we would like to let you know that we have provided the custom format support for negative valued cell while importing in our (126.96.36.199) version. Please refer the below release notes link.
We recommend you use latest version for scripts in your project and ensure whether you have referred the same version for both assemblies and scripts. Could you please check the above details and get back to us with more details including Essential studio product version, if still issue persists?