Heartbeat causing high CPU

Heartbeat causing high CPU in 5.1 Its everything updated, the theme is premium, support didnt told me anything helpful. I am using AdForest theme with 13 000 classified ads and for some reason using this theme i had CPU overload problems. I was always at red in my hjosting pannel. I changed my hosting plan to the biggest VPS plan and on the first day online … this time was only CPU limits to the top and that was until now I sow that admin-ajax was the causing problems script it was loading 5 000 requests for 1:30 h. So i descided to stop Heartbeat and for 2 days, no problems, only one time CPU limits exceeded for short period. I have tried with all plugins off before disabling heartbeat, and there was no result at all, so I guess its from the freaking theme, but support of the coders told me nothing, actually they didnt respond me at all for a wekk or so…….. The theme is on themeforest support ticket system so there is no phones etc. Tried mail, also no response. Is there any ideas how to fix the issue, I need the heartbeat because of autoposting plugin to social media.