Product: Credit card or prepaid card

I have been having a lot of problems with my Amex Card over the last months. 
Each time I try to make purchases, let us say 8 times out of 10. The bank will decline to pay the merchant and the resulting effect is a failed transaction. 
After each time, the bank continues to withhold my money during these failed transactions and their excuse is that it is pending transaction. 
How can a transaction be pending for an airline ticket that was not processed. 
The merchant could not get the money in each of these transactions and they go ahead to not issue the ticket, but Amex continues to tell me that the hold id on because the merchant has authorized the charge. " No ''. 
" This is an untruth '' none of these merchant had collected any money from this transactions. 

I have never seen a bank that collects people 's money and hold on to it while claiming it was collected by the merchant. 
Why is Amex now making this difficult for users knowing that they have to endure the hurdle of many merchants not even wanting to accept Amex. For example, transactions in the XXXX only accepts MasterCard and Visa. The lack of universal acceptance of the Amex card should be a factor in how customers are treated. There is need for better operational banking processes. 
If a person is buying an airline ticket that is in their name, what security issue is there for you to repeatedly decline the transaction until the customer calls you. if the customer has limited funds in their account, the transaction can not even be re-booked again and these are time sensitive transactions. This is unfair. 
As I speak now, over {$500.00} of my money is held up in " Processing '' status when the merchant had made clear that they are " not processing '' the payment! 
The merchant in this most recent issue - XXXX- had not collected any money from me the report is there in their website. 

I spoke to a customer service agent named XXXX and she was telling me that if a merchant make a request for a payment they will respond to the request to charge the account. But I asked her, what if the payment was not successful for any reason, and the merchant had not been asking you to send the money and had shown that the transaction had cancelled because the action to collect money had been truncated, would you still continue to hold the money? She said " Yes '' that is it they will continue to hold the money for up to eight days. 
I think this is preposterous and a gross disregard for the rights of the consumer. What this causes is that the money that is held up is unusable for the customer who needs to quickly book another ticket because buying airline tickets are often based on how early you do so or what ever flight is currently available because they go very fast. 
Amex will now as they have told me on the phone, keep on holding the money waiting for nothing, basically. 
This is unacceptable. 

Thought these actions, the bank had done a lot of harm to me and I am seriously now so stressed that I hate using the card for purchases. 
There customer service department does nothing to help customers in this situation and they should. What is the essence of a quality control or operational process to liaise with customers when it is not implemented in specific ways that it matters to the customers. 
The customer is king and this bank needs to realize that. 

This is the same way that they have refused to correct an error that they added to my report last year. They collected a false report and downgraded my card from a limit of {$2000.00} to {$1500.00}. I have been talking about this and had left so many messages when this initially happened. The manager of that department - 'The Responsible Lending Team'- at this time was obstinate about the report and refused to act on the true account which I had made evident since the same month that Amex had written to me that I have an adverse credit history and so my account privileges will be significantly reduced. 
This woman who stated that she is the boss in the department acted like a XXXX  and a XXXX  whose only goal is to revel in other people 's miseries. And I am being generous in my assessment. She was worse, kept telling me yes, it happens, and I should live with it. Blah blah blah. What? 
Since then I have experienced a lot of pain in using this card, they have marked it as high risk amongst other things. 

The report that they used to do this action, they need to produce it and I will want it to be compared to the credit bureaus. The credit bureau information will show the error and how they quickly corrected it. 
I have no delinquent history and no defaulted loans or anything like that. 
Why then did they not correct this problem and restore my card to the rightful status? 
Amex needs to do this within the next 48 hours. They need to restore my charge card to the original status. The card is the Amex Rewards Gold Card and I have been paying the annual fees which is almost {$300.00} every year for this card, and paying the balance in full every month. The management needs to see what these team had done to me. It is very wicked how they have treated me. 
Every month I pay the balance sometimes even earlier than it is due. These transactions have been showing that the credit limit is too low yet they had refused to do anything about this. 
The fraud alert on my report does not stop them, it is to protect unathorized applications for credit. I want this matter to be investigated because all my credit cards need to be upgraded another limits increased. 

This is unacceptable and I want them to stop trying to frustrate me with each use of this card. 
It is tantamount to discrimination to deny service to legitimate users in a manner that is commensurate to all other users. 
They can not demote my credit limit for false information that I had been at default with a merchant which at that time was XXXX XXXX XXXX  '