Sap Fico Support Issues

I have an issue....Check lot has been created and its sequentialy...and check lot is 058851-058950...now user is going to payment to the vendor through F-58 and 51 and 52 chk has been issued.now when nxt paymnt is going to make that time system is saying 53 and 54 chk voided by abc user.So next free number is 55.Now user is asking me why system behave like this without void any chks how system say 53 and 54 check is voided???I have also a doubt why system is saying like this????Please help me out regarding this issue....its very very urgent.....

First check the check register through T.code FCHN - Check Register. Suppose someone did di d manual check update

What are the Month End Closing Activities in Finance? 1. Recurring Documents. a) Create Recurring documents b) Create Batch Input for Posting Recurring Documents c) Run the Batch Input Session 2. Posting Accruals or Provisions entries at month end 3. Managing the GR/IR Account-Run the GR/Ir Automatic Clearing 4. Foreign Currency Open Item Revaluation-Revalue Open Items in AR.AP 5. Maintain Exchange Rates 6. Run Balance Sheets  – Run Run Financial Statement Version 7. Reclassify Payables and Receivables if necessary  8. Run the Depreciation Calculation 9. Fiscal Year Change of Asset Accounting if it is year end 10. Run the Bank Reconciliation 11. Open Next Accounting Period