Open the F_receivedpayments form as Dialog, so the code will pause until you
close the receivedpayments form, and then run the requery to refresh the  sub
form

Docmd.OpenForm "receivedpayments",,,,,acDialog
Me.[billsopenvalue].Requery

Hi klaus,

you would not requery the field, just the form.  if there is a subform then
you would need to requery the subform as follows

[forms]![mainform]![subform]

a good way to add payments would be to have a command on your main form
which when clicked would open a new form to recieve the data entry.  once
entered upon closing the data entry form the main form would be requeried

(create a small form to accept the data you want, include the id number
linked to the main form)

sometihng like

private sub cmdopenform_click()

dim stdoc as string

stdoc ="the form you want to enter the data in to"

docmd.openform, stdoc, , , acnormal, acadd

end sub

this will open the form in add mode

then you need a before insert event on the form to take the id ref number
from the main form to the sub form, this will ensure the record is attached
to the correct master record

private sub your data form_beforeinsert()

With Forms![your main form]
       If Not IsNull(!your id autonumber) Then
       Me.your id autonumber= !your id autonumber
       End If
   End With
end sub

then once you have entered all your data you need to close the from, the
best thing to do is have a command to save and close with code as follows

Private Sub cmdcloseSave_Click()
On Error GoTo Err_cmdcloseSave_Click

    Dim stDocName As String
   Dim stLinkCriteria As String

   stDocName = "your main form name"
   
   stLinkCriteria = "[your id number]=" & Me![your id number]
   
   Select Case True (you can use this to ensure all fields are filled in or
ignore the case select)

   Case IsNull(your field name)
       MsgBox Prompt:="You have not entered...."

   Case IsNull(your field name)
       MsgBox Prompt:="You have not entered...."

   Case Else
 
   DoCmd.DoMenuItem acFormBar, acRecordsMenu, acSaveRecord, , acMenuVer70
   DoCmd.OpenForm stDocName, , , stLinkCriteria
   [Forms]![your main form].Requery
   DoCmd.Close acForm, "the name of your add data form", acSaveYes
   
   End Select
   

Exit_cmdCloseSave_Click:
   Exit Sub

Err_cmdCloseSave_Click:
   MsgBox Err.Description
   Resume Exit_cmdCloseSave_Click
   
End Sub

i hope this all makes sense and will help you achieve what you want to do.  
regards  richard