To comply with GDPR we will not store any personally identifiable information from you. Therefore we will serve sub-optimal experience where some features such as Login/Signup are disabled. However, you will be able to search and see all the properties, see agent contact details and contact them offline on your own.
You can definitely surrender back your HDB unit back to HDB, subjected to approval. HDB will either allow you to market your unit in the open market or purchase it back at valuation price. Depending on your key collection date, you might be liable for Seller Stamp Duty.