How To Prevent Deleting Of Cells Missing Function Ranges

I have macro that brings information from outlook to excel. In the beginning of macro, it deletes range of cells. That destroys the functions that target those cells. Is there a way avoid that? Using some different method or ?

Code:

Dim olApp As Outlook.Application
Dim olNS As Outlook.Namespace
Dim myCalItems As Outlook.Items
Dim ItemstoCheck As Outlook.Items

[Code] ........

Running the macro messes up all funtions that targets those cells.

Like:

Code:

=DATEVALUE(MID(data!#REF!;4;2)&"."&LEFT(data!#REF!;2)&"."&RIGHT(data!#REF!;2))

This really great code to get data from outlook is originally: [URL] ........