Rather than a credit card

I have a "Load and Go" card from the post office. It works like a debit card. You can put money on to it at any post office and then use it wherever  you would use a Visa card within Downunder. There is a different sort of "Load and Go" for use overseas.
It is a good idea. It is a cheap alternative to a credit card if you only need to do a couple of transactions a month or you don't want a business to have your bank details.You can put just enough on to pay the bill or buy something.
Or rather, it should be a good idea. My card got "blocked" yesterday. It got "blocked" for the second time.
No, it was not my fault. I went online to try and check to see that the balance was what I thought it should be. I typed in all the necessary information very carefully...and was told that it was wrong. 
Now I was extremely careful. I didn't think I had done the wrong thing but there is always the possibility. You cannot read the dots and check so...I did it again. The same result came up. 
I knew if I tried again the card with the same result the card would be blocked. So I changed the password, received the requisite e-mail, and then tried again - twice. Still "wrong". 
Now, at this point, I have gone into the security and given the computer at the other end the "word" that only I know - and it is not a word that anyone else would know because I made it up. I think about it. I have nothing to lose. I change the access number as well and receive the requisite e-mail. 
Then, ultra carefully  - hesitating over each letter and number as I type them in I try again. I tried twice. At the end of the second time I was "blocked".
By then I had actually tried to access my details not three but six times. And yes, I had typed in the correct details - more than once.
There is, I think, something else wrong. I will have to contact them later this morning. 
I am not impressed. It reminds me of why I do not use a credit card on line. I remember the horror tale of my friend R who had a call from the bank. Had she, they wanted to know, just bought a car in Singapore? 
Of course she had not. She had not been anywhere near Singapore for several years. 
Her credit card was stopped. It was stopped in the middle of a holiday weekend. Frantic phone calls ensued and she was at the bank when it opened on the Tuesday morning.
The Senior Cat once had to borrow some money from a friend. They were at a conference together and the teller-machine swallowed the Senior Cat's card and refused to give him any money. He had to go into the bank the following morning too. It was his good fortune that he had other ID and a friend willing to see he could eat something.
I don't like this "card" business. I know it is the way the world is going but sometimes, just sometimes, it doesn't work!