Unable to use .(propertyNameHere) all the sudden

Question

So there I am testing a script using a typical $service = get-service followed by $service.name and nothing.  I get confused and hit $service and there is everything.  I try a few different commands and get the same result.  For some reason
I cannot use .property to get anything on any command I try.  No errors no warnings nothing.
Dislaimer 1:As usual I could be way off so no playing like I'm Frankenstein. Disclaimer 2: my Speeling and proofing skills are teh fail

Answer 1

so here is the full example:
$DatacenterName = Get-datacenter
$menu = @{}
For ($i=1;$i -le $DatacenterName.count; $i++){
    Write-host "$i. $($ClusterName[$i-1].name)"
    $menu.Add($i,($DatacenterName[$i-1].name))
[int]$ans = Read-Host 'Enter selection'
$DatacenterSelection = $menu.Item($ans)
Write-host ""
Write-Host "$DatacenterSelection selected."
Write-host ""
This was working just fine until about 12:15 then all the sudden i started getting:
21.
Cannot index into a null array.
At line:2 char:14
+ $ClusterName[ <<<< $i-1].name
    + CategoryInfo          : InvalidOperation: (21:Int32) [], RuntimeException
    + FullyQualifiedErrorId : NullArray
however when I select a number the proper name displays
I did however open another script that performs the same action just no using get-datacenter and it works fine.  I was looking for ideas.
Dislaimer 1:As usual I could be way off so no playing like I'm Frankenstein. Disclaimer 2: my Speeling and proofing skills are teh fail