Product: Credit card or prepaid card

I sent a security deposit to Citi to obtain a secured credit card, because I want to purchase a home next year and desperately needed to fix my credit. I sent {$200.00} and received my card. I was using it regularly, paid my first bill early and even paid roughly twice the minimum payment due. Well sometime before the second bill became due, I had a falling out with my roommate and had to move. During the move, I lost my wallet. I called Citi to explain my situation ( and got routed to the RUDEST, NASTIEST CSR I have ever had the misfortune of speaking to, mind you ) and explained that during the move, I had lost my wallet, I think one of the people who helped me move my stuff took it, because there was a charge I didn't recognize on the card. But I really wasn't sure and really didn't know them anyway. But I said I needed another card and also due to me having to move to the other end of town, I also had to change jobs, it would be a few weeks before I got a paycheck and so my next payment would be late. Again she was very rude, but ultimately told me that would be fine. Well a couple of weeks went by, and I received my new card and when I got my second paycheck ( my first was only for two days ) I go to log in to make my payment, and it said my username and password were invalid. I tried resetting my password. It said my email address didn't match any records! I called customer support to find out what was going on and was told it was a website issue. Called technical department and was told it was an account issue. So obviously I think my account had been closed!! No explanation, not a letter, not a call, nothing! Now keep in mind that the whole reason I got a secured card was to try to raise my credit score to buy a home, so this was a big deal, I assure you I reached out to them to let them know what  was going on. Yet they closed it anyway, with ZERO notice or warning, and now, my score is even DOWN 20 points! And because of that, I was recently TURNED DOWN for a SECURED card with a different card issuer!!! Like, seriously??? Not only was it ONLY my FIRST time missing a payment, but A ) It was only my second payment due, B ) I I had paid my first payment early AND double what was due, and C ) I had CALLED AND EXPLAINED why I missed my payment and was told it was OKAY! I'm very sorry for the caps but I am LIVID! So now because I chose Citi instead of the 100 other secured cards I COULD have got, instead of improving my credit score like it was supposed to, it has actually made it WORSE, AND it is preventing me from getting a card with other institutions so I probably won't be able to buy a home at all! 
But now here 's the real kicker. I just found out from them when I called to discuss making an arrangement to get it off my credit file, that my account did not get closed until OVER A MONTH LATER!!! The site wouldn't let me log I because I had not activated the replacement card I had just got!!! BUT the letter that came with the card said LOG IN TO ACTIVATE!!!!!!!! Wow! Seriously??? This was a big deal, I tried for DAYS to make that payment!!! I CRIED because I knew how bad having that on my credit report would set me back! 
These thieving, deceiptful frauds should not be allowed to have influence over anyone 's financial situation. To them it's no big deal, I was just another number/sucker but to ME, it is a HUGE deal because it put me in a HORRIBLE situation. I don't understand how it's even legal? Someone with a better score than me could drag a missed payment out for months, and STILL get all kinds of account credits and miles and rewards, but me, someone who LITERALLY paid them in advance, lol, MY account gets closed?? After ONE late payment?? AND even then it's because their website wouldn't LET me log in to pay, and their customer care reps played blame tag?!? No, that isn't right. Please help me. I wanted WHOLEHEARTEDLY to be a good customer and to build my credit, and I don't deserve this. 
Oh, AND because I had signed up for online statements, and my LOGIN INFO DOESNT WORK, I can't even login to see my transactions, history, NOTHING! And now that I'm filing this complaint, I see exactly why they do that : because I can't SHOW anybody what they did to me! This is INSANE. I feel like I'm in the twilight zone. 
Also, on an even deeper personal level, I was raised by my great grandmother ( rest her soul ) and she was a LOYAL Citi customer for as long as I can remember, until the day she died, and so for deeply personal sentimental reasons, I was SO happy to be a Citi customer, and I had such high hopes that they would still be ( one of ) my financial institutions well into retirement. Seriously. Like, this has hit me hard on so many levels. Anyway. That's all.