Restore points not getting stored even if memory enough

Hello,
I ran the command vssadmin list shadowstorage and the result is :
vssadmin 1.1 - Volume Shadow Copy Service administrative command-line tool
(C) Copyright 2001-2005 Microsoft Corp.

Shadow Copy Storage association
For volume: (C\\?\Volume{aa9b9a43-1f6c-11dd-8d89-806e6f6e6963}\
Shadow Copy Storage volume:
(C\\?\Volume{aa9b9a43-1f6c-11dd-8d89-806e6f6e69
63}\
Used Shadow Copy Storage space: 1.655 GB
Allocated Shadow Copy Storage space: 1.93 GB
Maximum Shadow Copy Storage space: 10.251 GB

That means i have around 10GB space for restore points. But I only see 1 or
2 restore points from today or yesterday only in the list of points. The
restore points are getting removed automatically.

Any suggestions will really be appreciated.