I'm a globe subscriber as well with 70 mbps speed. I've also experienced this a few months ago. What I did is I purchased a new router which will act as secondary router. (I strongly recommend ASUS Routers, if kaya sa budget or yung mga routers na may Beamforming Technology)
Yung mga default modem-routers kasi ng mga isp's natin are cheap and faulty so it's not reliable at all.