NOKIA 6020 HI MY PHONE SAYS "INSERT SIM CARD". I HAVE TRIED DIFFERENT SIM CARDS BUT NOTHING HELPS. I EVEN PHONED MY SERVICE PROVIDER BUT NO HELP

Did you mean your phone shown no sim card inserted even your sim card present on your phone?
Yes,Means,There are three possibilites to get this type of issue.
1.There may be a problem in your Sim card so try another one.
2.Check your Sim whether it's properly inserted or not
3.Your mobile is locked to particular network provider.
If your problem persists,After trying first two ways means definitely Your mobile phone is restricted by some network so try to unlock your mobile phone.For unlocking you can approach your service provider or else try to buy an unlocking service from any one of the online unlocking service provider like
MobileUnlockSolutions.com

one reason might be is that , your phone might be network locked and hence it is rejecting other SIM, If that is the case try unlocking your phone to use other networks, http://www.theunlockarena.com/ will help you with the process

Hi I'm a mobile phone Tech.

If your mobile phone is on a contract with a service provider, most of the times it will be locked in with them for the duration of the contract,
So if you try to insert a sim card from a different service provider, it may say "sim card not valid'
Try to insert your original sim card and see if that works.

Otherwise if this IS your original sim card and all of a sudden this message "sim card not valid" has appeared, then the sim card has gone faulty and you need to get a new sim card from your service provider eg... Vodafone.

Hope this is helpful
MobileJB

Are you looking for the security code to unlock the cell phone so you can use the phone with a different phone service provider/SIM card?

To unlock your mobile phone to use it with a different phone service provider/SIM card, please click on this link and follow my instructions :-
http://www.fixya.com/support/r4049238-unlock_cell_phone

If phone provider won't help then try this WEB site it provides security codes for a small price.
http://www.mobileunlockstore.com/?gclid=CKDb2_y2558CFSlJagodxBkDHw

try using the default security code 12345

insert sim card

The puk code is sim card spesific it comes with the sim card when you get it or you can get it by calling your phone service provider of the sim card to get the puk code.
if you have entered the puk code wrong too many times you will make the sim card useless and you will have to contact your phone service provider for a new sim card, it will probably cost.

Some 3360 and other models were manufactured for different markets and some of these markets didnt had the SIM card technology by the time this phone was released so:

Some 3360 dont use SIM and may not work on your cellhone provider.

Try asking your provider to see if you can activate the phone without SIM as some providers usually offered the service in the transition between technologies and standards.

Good Luck...

the problem is that has been refurbished, and nokia doesnt make those consoles anymore. I have one that says no sim card when there is none. try contacting your cell phone provider and see if the card is in good service also the sim card needs to be higher than 46k to run on a nokia phone or the console system. A good way is to restart the system on the phone. Make sure sim card is its right place, the game slot side