Slingshot unstable connection

Hi all, greeting from newcomer here.

I have been having connection issue with Slingshot UFB.

When first I moved to Slingshot UFB (30 MBps) it was all good, no issue and happy with it. December last year I checked Slingshot page, seem they did not have 30 MBps anymore and the 100 Mbps cost pretty much the same as the 30 Mbps when I joined so its no brainer I requested to be upgraded to 100 Mbps. The process itself seem to be taking months and I had to keep calling to request for updates.

Around February last month my connection suddenly just died, after few calling to Helpdesk I got the connection back by moving the cable on the ONT side from GE1 to GE2. I'm guessing that in order for me to be connected to the 100Mbps Chorus has to make some change to the ONT. At this stage the connection still in 30Mbps when I checked with Speedtest.net or linetest.nz (Im eventually get 100Mbps when I try to investigated myself and rebooting the ONT and router). However this is the start I'm having unstable connection issues.

What I'm currently experiencing now sometimes pages seem does not load at all, Internet browser show that 'Waiting from site....' and it stay like this until it timed out. I noticed this happen alot on HTTPS connection. I used Hotmail alot, when I opened www.hotmail.com it will load the page however as soon I login to hotmail, I experienced this issue and eventually show error "Secure Connection Failed". This seem the same with Facebook, Evernote and many other sites as well. However if I opened other site for example www.google.com it will open alright and I can search anything to confirm my connection is alive. I reported this to Slingshot but so far nothing works, I was asked to do Slingshot full throughput test which reporting all is good. I noticed during testing on speedtest.net or linetest.nz, the upload test very often timed out. I experienced this issue as well on my Playstations, iphones, and ipads. This issue happen alot but intermittent, after experiencing this issue if I waiting few minutes sometimes I can login to Hotmail fine.

Troubleshooting I have done

Rebooting my router, ONT, computers, many times.

Set DNS to Slingshot DNS or Google DNS

Re-plugging all cables

Test my PC to use tether connection from mobile phone 4G seem I don't have this issue (however I only test connecting for 1 hour)

Devices I have, 3 Ubuntu Linux PCs, 1 Macbook Pro, 1 Windows work laptop, 2 iPads, 2 iPhones, Playstations 3&4. So far I noticed the issue alot on the Ubuntu Linux PCs.

Any advices really welcome, I have going back and forth to Slingshot helpdesk and emails but seem not helping.. most of time I was asked to repeat the generic testing. If require more information I'm more than happy to provide. Thank you.

Edit adding notes from automatic respond:

you have reset your modem and router - I have rebooted my ONT and router many times

your PC (or other PCs in your LAN) is not downloading large files when you are testing - you are not being throttled by your ISP due to going over the monthly cap - I have check and ensure nothing downloading and I'm on unlimited connection. This issue was not there when I was initially on 30Mpbs.

your tests are always done on an ethernet connection to the router - do not use wireless for testing - Yes I'm using wired connection.

you read this topic and follow the instructions there. - I have read but unsure how applicable as I'm currently on UFB, not DSL connection.

Make sure you provide information for other users to help you. If you have not already done it, please EDIT your post and add this now:

Your ISP and plan - Slingshot 100Mbps Fibre connection unlimited

Type of connection (ADSL, ADSL2, VDSL) - Fibre

Your modem DSL stats (do not worry about posting Speedtest, we need sync rate, attenuation and noise margin) - How do I get this? I'm using the Slingshot provided Broadcom router supplied when I joined Fibre

Your general location (or street) - Sunnynook

If you are rural or urban - Urban

If you know your connection is to an exchange, cabinet or conklin - I have no idea

If your connection is to a ULL or wholesale service - I have no idea

If you have done an isolation test as per the link above - None as I'm on Fibre instead of DSL

I have also tried to change cables to ensure it is not the cable problem.