Credit card cut off dates and e bucks

I wish to express my dissatisfaction in the way the credit card cut off’s work. The month of May ended on 31st but my credit card expenditure up to and including 4th June (4 days after month end) has been rolled back into May. This makes a mockery of the up to 55 days credit statement and plays havoc with my cash flow. Further to this is messes up my e bucks rewards which has levels such as R2000 spend at Checkers so having spent R2000 in May my June purchases up to 4th count for no reward, likewise petrol and general credit card spend having reached targets in May also count for nothing. It’s a poor show when cut off dates of credit cards are not clearly known to the public. My correspondence with FNB lead to a 30 day cycle statement but no one could answer to what happens to the other 5 days in a 365 day year. I guess I have just found out where 4 of them went.