Dave is correct in that they ALWAYS blame the modem and tell you to contact the Manufacturer.(not just me, other fam members homes also) And no offense to CS techs, but we know the routine, we know you have scripts to follow, but spending hours going step by step with you to just be handed this answer every time is quite annoying!
I have had a problem for months(almost a yr) where mine resets itself at least once a day...but more often several times a day. I have same 150 preferred. One family member was told by cust service, that for whatever reason sometimes changing your routers password helps. I tried that and oddly it has for me. Instead of several times a day, might reduce to once a day or every couple of days. HTHs