Ghosted by UST Global after clearing all rounds and salary discussion

Recently, I cleared the technical + techno-managerial rounds of UST Global. Had a discussion with HR on salary and settled for x amount after negotiation, but later, I got ghosted from them. Got no offer or any further call. They dumped the requirement or might be looking for cheap talent, but why would keep my efforts in the loop? I don't know what to do next.