Product: Credit card or prepaid card

I was recently sent an offer by XXXX  to acquire the Delta Sky Miles XXXX Card which I decided to acquire. I have been an XXXX carrying card member for over 37 years and pay my balances in full every month. I have two XXXX  Delta Sky Miles XXXX  Cards one for business and one personal along with another XXXX   XXXX XXXX Card and spend over {$100000.00} a year amongst them. Therefore in addition to the fees I pay to XXXX to have these cards yearly I have charged millions of dollars on these cards over the past 37 years using them. I requested an increase in the newly acquired Delta Sky Miles XXXX Card  balance from the initial {$8900.00} balance they set on the card to {$45000.00}. I applied for this increase in the early part of XX/XX/XXXX, and faxed an IRS transcript request and was told I would have an answer in three to four days concerning my request. When I arrived back home from a 10 day business trip on XX/XX/XXXX I had a message on my home phone answering machine from a XXXX  employee named XXXX who works in their underwriting department. He left a message that he was going to go ahead and process the request and if I had any questions to call his direct line at ( XXXX ) XXXX. I tried reaching him on at least 15 occasions but all I ever got was his voice mail and after leaving messages never received a return call. I continued to follow up through the number on my card and all I ever got were representatives in XXXX who gave me the run around and failed to assist me or provide me with any information other then the request was in underwriting. I telephoned the corporate offices in New York but they would not put me through to anyone in the corporate headquarters since they are told to block calls from customers. On Monday XX/XX/XXXX, I reached out again and was told my request for the XXXX Card increase was denied and was not told why. I then requested to speak to a supervisor and was put through to an employee located in Georgia at which point I requested a balance transfer to the Delta Sky Miles XXXX Card from one of my other Delta Sky Miles XXXX Cards. I need these higher credit limits because I make large tax payments in my XXXXXXXX XXXX XXXX located in New Jersey. On XX/XX/2018 I received a letter from XXXX advising me that my request for the credit line increase was denied because my recent spending on the account is low in relation to the current initial {$8900.00} limit they gave me on the XXXX  Card. These incompetents did not take into consideration that I had to use one of my other cards to pay {$20000.00} in taxes and could not use the new Delta Sky Miles XXXX  Card for the payment because the limit they set was too low. Thus the reason for my request for them to provide me with the credit line increase I was requesting. I wasted over 6 hours of my firms billable time on this and had to transfer my line from another card in order to derive the sky miles I need to earn to keep my XXXX  status with XXXX XXXX. Therefore their promotional materials concerning how you can earn XXXX XXXX   miles is a deceptive trade practice since they set the card limit low thereby making it very hard to earn the sky miles required to secure XXXX XXXX Miles. As a person with an excellent credit record they have harmed me and denied me credit for no valid reason. Moreover, they have trained their employees to give creditworthy customers the run around instead of providing prompt and meaningful responses especially since most of their representatives are located in XXXX and are of no use.