The Lohspeicher website contact page has their email address:
KONTAKT
If they don't respond at this time of year, well, that's not really unusual for family-run German inns that operate seasonally. Some owners take month-long vacations at this time of year. Or they at this time be paying attention only to the online bookings they get through their website or booking.com.
You can check availability for the dates you like at THIS PAGE on their website. Enter your check-in and -out dates using the pop-up calendar and hit "Verfügbarkeit prüfen" (check availability.) Available rooms will pop up. Use an online translator for copying/pasting the room description? You can at least see if they have what you're looking for. Prices start at €90 for double with breakfast (a tad high for Cochem.)
You can also click on "accommodation request" through the Cochem Tourist office and request an offer from the Lohspeicher using THIS PAGE.
I haven't stayed in Cochem in some time. I recently booked a single at this B&B place with 9 rooms near the castle, and not too far from the Lohspeicher, for my nephew (via email.) He loved it and enjoyed his chats with the owners and locals that stopped in for an afternoon glass of wine. Doubles run from €48 to €57 with breakfast.
Zum Fröhlichen Weinberg
email: [email protected]