Pingplotter Alternatives

I am looking for something that I can replace PingPlotter with. I work for a small ISP with about 30,000 subs and we use Pingplotter for customers that are having issues with connectivity. We normally have anywhere from 10-30 subs in PingPlotter at any one time with a customer's IP being in the software for anywhere from a few days to a few months. We have the software installed on a VM and use the PingPlotter's web interface for level 1 support to enter customer modem IPs and level 2 will monitor the customer connectivity through PingPlotter. I don't think it was quite meant to be used like this but it was something I inherited when I took the role.

The problem is the VM gets locked from time to time by the PingPlotter Windows service. The solution is normally to reboot the server and allow the service to come back up but sometimes that doesn't work and the service hangs. We have even tried building a new VM but it eventually starts doing the same thing. I have tried using the cleaning tool from PingPlotter to clear out old data but it stopped helping after a while as well. It is becoming a huge time suck and not worth the effort but the call center insists on having something.

So what I need is an alternative to PingPlotter that can monitor an IP over time, has web based entry as many people enter data and can be centrally managed by multiple users. I thought about something along the lines of an NMS but feel that is overkill for what this is used for. For all of the "need" for it, I know only a handful of our tech support agents even use it so I don't want to put a lot of money into it a replacement either.