Samsung BioLogics interview questions

They asked some technical questions regarding my previous lab and internship experience and also some more creative questions such as hypotheticals and miscellaneous questions (like what fruit would you be).

The interview process was very concise and short. Resume screening. Telephone round. Tablue Test. After these I got a call from hr that I have been selected for the job and I just have to submit my documents for them to release offer letter and do tableau certification within 15 days. I can call them back for any queries. I shared my documents and it's been a week since I last talk to them. They are not picking up my calls neither respond to any of my emails. Why tell me I'm selected then not pick up my calls? I do not know what to do and how to contact them.