Change in Port of Arrival

I recently called the JHB office on the following numbers *** & *** and spoke to a front desk lady, who kind enough to transfer the call to the actual sales rep/manager (calims was made). The personal name was Abdul Mottou and wasn't very helpful and extremely rude over the call, where at one point even started raising is voice in not providing assistance and when logical questions were asked about a change of ticket

I had purchased a ticker with Air Seychelles for a trip to India, where the travel plan is for in the 3rd week of Jan 2020, I was requesting to change the port of arrival to a different state for which I had extremely weird answers like " I need to travel first in order to change the port of arrival" Which doesn't make sense. I even advised that I am ready to pay extra charges on top to make necessary changes which was also rejected point blank giving a lame reason

I wish someone from the concern can really help as I am getting no where with these issues of the airlines