Communication from IT Deptt. that i chose wrong nature of busines

Sir/Madam I had filed my income tax return online and on time. I am working as a consultant with an International NGO and get paid after completing certain deliverables based on the invoice i raise after an interval of every few months. I consider myself a professional as i do not get a salary and am paid based on a contract as i quote my own fees. Secondly, i have to incur some cost to meet those deliverables. I had filed ITR-4 under 44ADA and recently i got a communication from CPC u/s 139(9) that it is defective. Error code is 89- The provisions of Section 44ADA not applicable to the taxpayer. The nature of business code in Sch NOB is not a profession, and the income disclosed under Section 44ADA income is more than zero. Hence the provisions of Section 44ADA is not applicable to the taxpayer. Probable resolution given is : The provisions of Section 44ADA is applicable only to Professionals with nature of business codes of 601 to 607.Taxpayer is requested to furnish correct Return Form type,i.e.ITR- 3 or ITR- 5 as applicable. If the Income has been disclosed under incorrect Section, the correct Section of the Schedule BP may be filled. If the Nature of Business code entered in the Return filed is not correct, the correct nature of business Code may be entered in the Sch NOB and the Corrected Return may be filed. Kindly advise what should be my next course of action. Regards,