I Can't Reach Stayforlong to Modify My $395 Hotel Reservation

Through Stayforlong, which we were directed to via Trivago, we made a reservation at the Ramada Encore by Wyndham İzmir hotel for the dates June 19-21, 2026, for 2 rooms, 2 people, 2 nights, totaling $395, paid by credit card. Our receipt number is P439N6.
After purchasing our reservation, we wanted to push these dates back by 1 week and add one more room to our existing reservation. Despite contacting Stayforlong repeatedly via email since Monday, we haven't received any response at all, and we also can't reach any phone number belonging to the company. This situation is causing both a waste of time and serious uncertainty in our accommodation plans.
Our request is that our existing reservation's dates be moved forward by 1 week, and that one more room be added under the same conditions. We want an urgent written or phone response regarding this matter, and for our hardship to be resolved.