USAA CREDIT CARD .CANT COUNT ON.Credit card.limit reduced without notice

I am bothered that USAA can reduce credit limit like a light switch.USAA recently reduced my credit limit by 40% because I guess I had used too much credit.I made a large purchase and the limit was reduced which doesn't make sense because BOA had just increased my limit to almost twice.USAA is getting too putty and what bothers me most is that if I had been overseas on travel and depended on the credit card,me and my family would have been stuck in a foreign country with no funds.I payed off the card and will not trust taking any USAA credit cards for.emergency backup when I travel.The lady at USAA credit card dept seemed not to give a rats azz when I complained.