Nedbank randomly changing the payment terms of my home loan

I took out a home loan with Nedbank in March 2015. This was over a 240 month period. Writing now in January 2021, 70 months have passed. 240-70= 170 months remaining on this bond.

I have just come off the phone from Nedbank - apparently I have 189 months remaining on this bond (???). My latest statements shows the bond being over a 196 month period (???).

Even given that I took advantage of the 3-month 'holiday' during hard lockdown (April 2020), none of these figures make any sense. I have just spent more than half an hour on the phone to Nedbank - nobody is able to help.

This is ridiculous. It would appear as if this account has been tampered with. I would like a clear explanation from Nedbank as to exactly what is going on.