This is unfortunately a common problem in Malta, and there are sometimes nationwide shortages of certain brands of contraceptive pill.
You should first speak with your doctor to see if they can prescribe a similar type of pill. If this is not possible, or if other brands give you side effects, consider buying your contraceptive pill from an online pharmacy abroad such as this one.
Since online pharmacies usually only ship to their own country, you could try a send on service such as Maltapost SendOn. It is legal to import prescription medicines for your own use.