Hi I used a similar setup on Cayenne My Devices but when they switched off the free platform we moved the system over to the Arduino IOT Remote app but it is not very reliable and limited, I preferred the Cayenne solution. Are you still using your controller and if so where have you migrated it to?
This has me worried now. I always configured my ADSL router myself and never had such issues. I am VOX ISP user for many years and was mostly happy with the ADSL service. The one or two outages I had (few and far inbetween) was normally a copper issue which Telkom fixed quick enough if I nagged...