Product: Credit card

Hello, I had a Venmo Credit Card that Synchony Bank is the issuer. The credit limit was {$6000.00}. I have had the credit card since approximately XX/XX/XXXX. I was told I was late on payment XXXX time in XX/XX/XXXX for 1 day, which was when I changed bank accounts. I accepted a new job XX/XX/XXXX which included travel reimbursement. I decided to pay off my Venmo which had a balance at approximately {$5800.00}. They kept the funds for XXXX weeks until the payment cleared even though it was just a couple of days. During that XXXX weeks they gave me a {$50.00} dollar credit limit. This isnt my complaint, but just info. I did call to confirm I still had the $ XXXX limit and it was confirmed. The funds were available on XX/XX/XXXX. On XX/XX/XXXX, I went to make a purchase for my job and the card was declined. During my call to confirm my $ XXXX balance, the rep told me if I travel to call and let them.know so there would be no issues. That is why I thought my card declined. When I got home I looked at my account and noticed my credit limit was changed to {$1000.00}. I called and was transferred to a XXXX. I explained what happened and he told me nothing could be done and that I signed terms and conditions that my limit could be changed. I explained to him that is was ironic that as soon as Venmo/Synchony couldnt take advantage of a high credit balance and capitalize on finance charges, my limit was dropped. He implied because of a letter received from the credit bureau they lowered my credit limi, which again is very ironic. I explained to him I hadnt been late and he said they have the right. I explained to him it was taking advantage of someone who has poor to fair credit by charging finance charges and asked him to either acknowledge yes or no, and he would not answer to either. I requested for him to reinstate my $ XXXX limit and he said he couldnt do it. As the call was about to end ( he kept talking over me ) I asked for his name and he refused to provide the name and hung up on me. Keep in mind Synchony did this exact same thing to me a few years ago at a furniture store. I made a large payment and immediately my credit limit was lowered. Just recently my spouse had the exact same thing occur, once a large payment was made to Synchony. The last thing, the XXXX said he couldnt reinstate my credit limit, but approximately XXXX mins after my call/complaint with the XXXX, my credit limit went from {$1000.00} ( which was lowered on XX/XX/XXXX ) to {$860.00} which is what is currently my balance, all due to work. This is unethical and taking advantage of people. This affects my livelihood. I understand if I hadnt paid my bill on time, but I have been a good customer and they simply took advantage of me. My thoughts are Synchony is they give credit to people who they think will consistently pay the minimum due so they can take advantage of high finance charges. If this avenue can not help me I do plan to conduct a class action lawsuit against Synchony. The XXXX obviously retaliated against my complaint and the questions he would not answer. They claim a letter was sent to me indicating such actions, but I have not received anything.