[Other Ubuntu/Debian based] FTP & mounted samba share - read only

Hello guys,

I have vsftpd installed which works ok. However, the space is very limited therefore in order to extend size I decided to mount a samba share which is located on another server. It is mounted using cifs to a folder within the ftp tree. From server which hosts samba I provided full read/write permission (777). Ftp user on vsftpd setup also has full read/write permission on ftp. But, this user has read/write permission only to a directories which resides on vsftpd host, write is not permited on mounted share - only read and directory creation allowed, can't write files into it.
When doing ls -la on vsftpd host to check mounted share permission it has 777 permission, but when writing file through ftp - permission denied... Can you advise, please?
Thanks.