Your personal loan application probably wasn't approved due to bad credit history. One way to improve your credit history is to apply for a smaller personal loan. Once approved, be sure to not miss any payments and be prompt with all repayments. You might have to borrow and repay a small loan a few times which gradually builds up your credit score. When your credit score improves, banks are more likely to grant you a bigger personal loan.
Restructuring all your outstanding debts is another possibility. If your credit score is really bad, you will not get any loans from any bank. So, settle all your outstanding debts first. A new option to consider is called a Debt Consolidation Plan (DCP) offered by most banks. Your preferred bank will pay off all your outstanding debts with other banks and consolidate them into one new loan. You'll be charged a lower personal loan interest rate than usual. The DCP needs to be repaid in fixed monthly instalments over a period of up to 10 years. The minimum amount that can be consolidated under the DCP is 12 times your monthly salary.
Non-bank financial institutions such as Hong Leong Finance and Singapura Finance also offer personal loans. While they consider your credit score too, they sometimes have different risk appetites and packages. For example, their personal loan interest rate package may be higher compared to the banks. Your last resort can be licensed moneylenders, which is not advisable. Their rates for personal loans are much higher than those offered by banks.