Complaint sub-issue: Problem with customer service

My problem started last year with Discover ( XXXX ) but since they cant seem to find the record of the conversation I had with them, there is nothing they can do about it. So they say. It was about lowering my interest rate. So now it brings me to the more recent problem, which is again, about my interest rate. On XX/XX/XXXX at XXXX I sent a message asking what my interest rate is, ( I have screenshots of everything ) On XX/XX/XXXX XXXX I received the following messages, Hi, Im the Discover Virtual Assistant! If I cant answer your question, Ill connect you with to a live agent. The very next message I got was XX/XX/XXXX at XXXX, Your current purchase APR is 20.24 % variable. You can also find the APR on  your statement. Simply tap the menu in the upper left, then Account, then Statements and choose the most recent month. I then replied on XX/XX/XXXX at XXXX, How do I lower it? Or do I just have to switch credit card companies? on XX/XX/XXXX at XXXX I was connect to a live agent and received the following message, I definitely understand how important it is to have a comfortable rate. Id be happy to reduce your standard APR of 20.24 % to a 17.49 % variable on new purchases. Is this something youd like to get set up now? On XX/XX/XXXX at XXXX I responded with, Sure. Thank you. On XX/XX/XXXX at XXXX the live agent responded with, No problem! The rest of the conversation is irrelevant ; however, I am posting pictures of the entire conversation. XX/XX/XXXX I called into discover because I saw an interest charge of just over {$25.00} and I know that number wasnt correct, given the new interest rate. When I called, I was told that the agreed upon amount was 18.49 % not 17.49 %, and that this kind of thing happens often. I explained to the girl that I have proof that we agreed upon 17.49 %. She didnt budge and told me in the notes it says 18.49 % and she even called over to the messaging center that I spoke with and they said they were showing 18.49 %. I took the 18.49 % change and was refunded my interest rate. I figured, maybe I was remembering it wrong, so as soon as I hung up, I checked the messages, and found that I did agree on 17.49 % NOT 18.49 %. I call back, and get a very helpful lady on the phone. But, I also go back to messaging Discover. On XX/XX/XXXX at XXXX I sent the following message to Discover, I just got off the phone with someone because when I messaged you guys on XX/XX/XXXX you told me you could lower my APR to 17.49 % and you never lowered it. Now she said when she called over to you guys you told her we agreed on 18.49 %. I can see the message where I was told 17.49 % please fix this and I would like a confirmation email that my APR has been lowered. On XX/XX/XXXX at XXXX I was transferred to a supervisor. I received the following message on XX/XX/XXXX at XXXX Hello ( My name ), I do apologize for this inconvenience in the difference between the reduction rates to your APR. I understand how important it is to get the lowest rate possible. After reviewing the messages weve had with you, I see on XX/XX/XXXX is when the option was presented however we did not receive a response from you until the following day meaning it was a new conversation when dealing with the APR we would be starting over in covering the offer. On XX/XX/XXXX you chatted with out automated system and you were asking about a possible lower option as you had offers from different banks. We still never got back to covering the offer and getting it accepted. Since then we didnt have contact till today when you called, given the time that has passed not all offers are the same from the day given this would be the reason as to why the reduction changed by a percentage. I know this is flustering in thinking a promise wasnt kept but due to not having your answer in the same day we were not able to accept the reduction on that day for you. Now the best option I have available as I see you did not accept the offer provided today. I can offer you a 0 % APR promotion for future transactions this would mean you have your APR reduced while getting a 0 % promotion for 12 months then after expiring you have the reduced APR. Would this be more to your liking? Now, Earlier on the phone I was told that I agreed to 18.49 % according to the messages that they reviewed, now he is telling me that I never accepted anything? Which is it, did I accept an offer or did I not respond? Also, when you do the messaging center, you talk with the automated thing first, so when I was talking to a person it was very clear to me that I was, in fact, talking with the same girl that offered me the lower APR to begin with. When I accepted the rate she even replied with, Sure!. 

After this whole ordeal I was told that my complaint would be sent to HQ. I never heard anything from HQ, so again, I go to the messaging center and they will not give me any contact info what so ever. I want to make sure that nothing is covered up and that my issue was in fact sent to the appropriate people, but since I cant confirm that, I have been letting everyone know how dishonest this company is. It is the sole reason that my husband will not open up a credit card with them and we will not be opening any other accounts with them. 

My name in the screenshots are covered for privacy.