iPhone not opening with correct passcode after changing SIM card

I have changed my sim card with new one in the same country, after that passcode required to open my iPhone, I entered my passcode and I'm sure its correct but it shown wrong passcode I have tried many times but still same problem, I have 2 more chance to enter it and I don't want to reach the final step which should i format it because I have important date and I don't to lose it, please any way to solve this issue.

[Re-Titled by Moderator]