If someone has changed the number of your phone by changing the SIM and this has been done before you login to the SaveCell web site to request 'Wipe My Contacts', you will be unaware of that change.  If the SIM change has been seen by the SaveCell Vault before you login to Wipe your contacts, the SaveCell Vault will have innocently recorded the changed phone number associated with that phone (the SaveCell Vault knows the electronic serial number of your phone - the IMEI - as well as your phone's number and records your phone number against the IMEI).  Part of one of the standard features of the SaveCell solution is that it is able to carry on preserving your contacts even if you get a new phone number and hence new SIM in your phone, or you have two SIMs, as some people do for local and international use, and you continually swap them.  

However, if your phone has been stolen and the SIM swapped and you were not aware of it, your login to the SaveCell Help page to Wipe your contacts would fail as the Phone Number has changed and the login that you think would work would be invalid.  All is not lost!  The SaveCell Vault is smart enough to remember the old phone number/numbers you have used for your account.  Hence the SaveCell web site will still recognise you from your old Phone Number and Username, you will be able to log in and you will be able to issue a 'Wipe My Contacts' request which will go to the new phone number and not your old one.  The Wipe form will be filled in appropriately.  If you do log in with a previous phone number, the SaveCell Help page will show the number you used to login with and the new number that the phone has at the top of the page.