Delhi Development Authority [DDA] — dda housing scheme 2019 online cancellation link problem

I, ritu rani, application number 109689, tried to upload documents for online cancellation of flat in lig which i was allotted after draw result on july 23, 2019.
I was not able to upload cancelled cheque and without that the form was submitted and now i'm not able to upload again or make changes.. I cannot find any proper helpline number working or any email detail through which i can contact the authority.
Kindly tell me what to do and where to send the documents.
This was the worst site which is filled with so many problems and no link to clarify the doubts and even faqs are for the outdated schemes.