QK doesn’t respect signed offer letter - Business Analyst QualityKiosk Employee Review

I had resigned based on offer letter from QK before Covid 19.My offer was deferred by HR on call saying u can check for other jobs as currently no position are open.Recently got another call from HR saying if I would negotiate on signed offer letter and if ready to work on 3rd party payroll. I would request to resort this organisation as last option or in desperate need only.