How to request a recalculation of Self Assessment from Revenue

I contacted the revenue and asked them to send me a reassessment for the year 2017 though the MyEnquiries function on ROS. This reassessment was required as I owe tax due to an early exit of an EIIS fund. The assessment has now been completed for 2017 but the tax owed is very high and I feel their is errors in the assessment by the revenue. Can I request a recalculation or what is the best approach to take with the revenue?

Is it not just a fixed percentage of the EIIS investment amount?

e.g. 30% of €50k

No, my investment portion in this company was 9578. The assessment is looking for 8969 in tax. I need to get this rechecked with the Revenue but I am not sure the best way to go about it.

Is your assessment a "Revenue assessment" or a "Self Assessment"? That is an important distinction and will dictate the answer to your question.

It is a Revenue assessment that I requested through ROS for 2017.