It's so rotten when a holiday ends up being such a let down. You have my sympathy OP.
I will say we've just got back from Antalya and had a great holiday. If you're anywhere near Side go to the ancient city. Easy on buses, land train down to the town which is gorgeous to wonder round.
Keep going to the marina and Apollo's temple. Loads of bars / restaurants & scenery to explore. Can recommend Twins restaurant down there for decent food and kid friendly service.
Cost €1.3 each from our hotel on bus (~20 min trip) + land train and free to see everything other than the amphitheater, so ridiculously cheap day out.
Look at excursions. We did a cheap one with Jet 2 (sure other operators will do the same) that went to Manavgat waterfall and a river cruise. Was £28 for an adult, £14 for kids including lunch, visit to Mosque, Bazaar, textile outlet for some shopping, cruise with a couple of hours for swimming, and lots of gorgeous scenery.
If you happen to be anywhere near the Adalya resorts the beach down there has wild turtle you can see on a morning if you walk along to the bridge. Kids loved this little outing.
Go for a Turkish bath, they catered to the kids too and they loved it. Think most resorts had an excursion of some sort if no spa on sight.
Keep trying with both the staff and travel company re complaints, take lots of photos for evidence to support your complaint, but try to make the most of what's left of your holiday. We were in a hotel that's mainly for German / Russian tourists but still found some staff had great English so keep trying for some help with your complaints.
I'd go back in a heartbeat for anyone fretting about upcoming trips. Beautiful area, lots to see, gorgeous beaches with water warm enough for the kids to be in all day, and only met friendly helpful locals - no harassment or overt interest / perving on my teenage daughter or younger blonde one (something my DM remembers from taking us as kids). All inclusive food a bit samey but I've never been to an AI that wasn't.
Hope you mange to salvage something of your holiday.