Modem randomly resets/reboots!

RCA Modem from Comcast is connected to our phones and internet.

Since the beginning of August it seems to like resetting/Rebooting itself.

Which is causing drop outs of the internet and phone.

I've called and they replaced the cables from the phone pole.

Yet it still happens.

Would this be caused by a defected Modem?

It does sit in a room where it gets really hot and humid.

The modem seems to be the last resort that I can think of.

Anyone with Any ideas?

If you guys agree it's probably the modem then I shall get it replaced.