My signal keeps sayin SOS and it tells me to insert sim card when

simple,try a different sim card to your phone.if it has a signal,means your old one needs to throw and get a new one to use

switch off your blackberry, remove the back cover and battery, and remove the sim card. Replace it after about one minute and it should not read SOS anymore.
If it still reads SOS, insert your sim card into another cellphone to see if it also reads SOS in a different phone. If it does, you need to call the company you bought the sim card from.
Eg; if it's an MTN sim card, call MTN; if it's Vodacom, call Vodacom etc.

try to type 0000

your phone might be locked to your network provider. try unlocking it. there are many ways to unlock a phone. you can unlock it using software or hardware or through codes. if you ask me the codes are the best way to unlock it. unlocking through codes is the best and simple way to unlock any phone. i got my phone unlocked through this method only. you can get the codes either from your service provider or from any other service providers. getting codes from your service provider can be got only if your phone is within 6 months of the contract period.. i got the codes from a third party TheUnlockArena.com provider.

It means your phone is not receiving signal from the network. First turn off your phone, remove the battery and insert in back in, then you turn on the phone. If it still does not receive signal, then you go to the phones menu, scroll to settings, then you select the network settings, after that select the manual network search, then a list will be searched out, select the network operating network of your Sim. If it still does not see the network, then it means there is an internal problem.
Hope this information helped.

its because of sim card error please insert some other sim card and on it for at least 5 hour once mobile frequency clock will set to new sim card then re insert old sim card it will take effect 100 %

Replace the SIM Card with your service provider

you are not getting the network signals.

usually SOS comes up when you are out of signal range or if you dont have sim inserted.

If you do have a sim inserted, try taking it out and giving the contacts a clean on the sim and phone

i bought my phone throught e-bay too i got optus sim card ask me about secuirty code (sos) i just put 4 zero ( 0000) the phone accepted and un locked try that