Product: Credit card

My daughter forwarded a link for a Capital one credit card referral. I used the link and applied for the card and was approved. The promo materials said my credit report would not be affected until I was approved. 
On XX/XX/XXXX I received a letter of approval for a XXXX XXXX credit card issued by Capital One with a credit limit of {$10000.00}. The letter said the card was being shipped and I should go online, set up an online Capital One account and track the card. 
When I tried to set up an online account I got an error saying this account was already tied to a user. I was directed to call Capital One at XXXX, which I did on XX/XX/XXXX. I was told I needed to supply my full social security number in order to set up the online account because there must be an error on their end. I resisted and hung up and continued to search for a way around this. I was unsuccessful and decided to try again later the same day. This time the person I spoke to insisted that the only way to do this was to provide my entire social security number. So, frustrated and uncomfortably, I did. She then said there had been an error ( which I doubt because if there was a mismatch the credit card shouldnt have been approved. ) But she said she corrected it and I could go ahead and set the online account up. I was able to so felt a bit more comfortable. The online account showed an open line of credit of {$10000.00}. 
I received my card in the mail and called XXXX to activate it. No problem. 
Since I applied for this card for some upcoming travel, I decided I should try to use it to be sure it worked. On XX/XX/XXXX I attempted to use the card for a small transaction at a XXXX XXXX. It was declined. I came home, called the number on the back of the card and was told the card had a restriction on it and I would need to supply the last XXXX months of income statements to verify my income before the card would actually be approved and before I could use it. I was already suspicious but thought it was a very deceptive business practice to issue a letter saying I was approved with a {$10000.00} limit, sending me a card and activating it, insisting I provide my entire social security number in order to set up an online account. I escalated the call to a manager who told me the same and said there was nowhere else to escalate and that it was just their policy. I would have to furnish the wage statements before I could use the card. Luckily, I wasnt out of the country with no other credit card with me! 
Frustrated, I asked to cancel the card. Most companies will do anything to not lose a good customer, ( XXXX XXXX of XXXX ) but she almost immediately said OK and canceled it. I asked her to email a confirmation, she said they dont do that it would come in the mail and that I would have to verify my address in order to get it. Again, pretty suspicious! Moments later, I received an email with the cancellation and checked my online account and it said it was cancelled- the account closed! 
I have a major concern. Either there is a fraudulent ring operating within Capitol One and collecting customers critical and highly private information or Capital One has fraudulent, misleading and deceptive practices in place.