Dial 12300 from your mobile phone and follow the voice prompt; 2. PIN and PUK. If you SIM card is blocked, you have to enter your PUK number in order to unlock your SIM card; 3. Airtime. If you need more airtime you can buy a tn mobile recharge voucher at any Teleshop, tn mobile distributors’ points or via FNB; 4. How to recharge?