Non existent banking security

For the last 2 weeks I keep getting -R3 everyday because of ‘international debit card declined’. Long ago the same happened. When I phone they tell me I must get a new card or contact the international company. (Like that’s going to work) So I got a new card and last week it just happened again. This is ridiculous!!! I’m not going to get a new card every month at R70 per card just because your security is below standard! Please sort this out or I’m going to sue and go to a new bank!!