ACT Broadband - Speed drop issue not being resolved

I've been observing continuous speed drops from the beginning of June ****, my actual connection is *** mbps, but suddenly my Download speed drops to less than ** mbps, where as upload speed remains fine.

When I raised a ticket for this (on *-June-****) , ACT Field engineer (Ahmed) called me said he wanted to visit my home within * hours (note: it was during lockdown relaxation time) and I agreed for his visit, came to my home and waited for him, he didn't visit, then he stared calling me around * pm (when I was busy with my online class - I am the instructor) and as I missed his call, he closed the ticket.
Next day, when I reopened the ticket, he called me and started scolding me, he said I should've called him directly rather than reopening the ticket, and now because of me reopening the ticket, he'll lose his job.
After disconnecting the call, he again closed the ticket. Then next day again I tried calling this guy, as I was observing slow speed, he didn't take my call, so I reopened the ticket. Then finally, today (*-June-**** at *:** pm) ACT engineer (Syed Hafiz) visited my home and he unplugged and plugged in my WAN cables, then asked to perform speed test, this time, speed was fine, then I shown the screenshots I took which clearly shows that Download speed is very less but upload speed is good, he said he can't do anything if the issue isn't live, and said it might be due some errors in fiber. And simply left the premises.

I don't have any other provider in my area for internet connection, that is the reason I've to bear this guys. I'm attaching the speed test screenshots with date and time as well.