Is being cashier hard?

I applied as a cashier and after my 5 day training. They say its 7 days training but The boss said its my last day today as a trainee (5 days) gave me my allowance/salary $26 in my country (Philippines) and he will call me if they have open position again they say they still have many cashier I got it meaning he doesn't want me. I mean I got what he means maybe he doesn't want me. I graduated college but Im not good at memorizing codes in the supermarket that I applied to. Some junk foods doesn't have bardcode so I always ask whats the code cuz I always forget it. Some have barcodes on it but the price is wrong so you have to type again the code of item. Maybe thats why they let me go.
Is being cashier hard?
Post Opinion