Product: Bank account or service

My complaint today is regarding XXXX. I established my account ( # XXXX ) in XX/XX/XXXX. Every month since, I have had issues with the posting of transactions to the account and overdrafts taking place on the account. For the most part XXXX has worked with me regarding these overdrafts by properly explaining the posting process of transactions and reversing some of the charges. The most recent chain of events took place starting on XXXX/XXXX/XXXX. 
I will religiously review my online banking account ( which they have since told me is not a good source because the history they provide is not same day activity, even though it shows that it is ). I have also set up my account to get email notices regarding my balance and any transactions that I need to know about. 
On the eve of XX/XX/XXXX I submitted a payment from my checking account for XXXX for {$79.00}, at which time my online banking showed a balance of {$640.00}. According to the agents I spoke with on XX/XX/XXXX, a transaction of {$640.00} debited my checking account on XX/XX/XXXX this activity did not reflect until the following day XX/XX/2017. Throughout the days from XX/XX/XXXX to XX/XX/XXXX my account reflected good standing. Of course because of their website having security locks, I was unable to take snapshots of the account activity. 
On the morning of XX/XX/XXXX I received and email notice ( see attached ), at XXXX that I received and overdraft. I check my online banking account to see that this overdraft fee was apparently charged on XX/XX/XXXX and backposted to be the very first transaction on XX/XX/XXXX. Please understand that this overdraft fee was NOT reflected anywhere on the online banking throughout the day on XXXX/XXXX/XXXX. Also note, this overdraft fee is for the transaction on XX/XX/XXXX, which again posted at night and backposted for that morning causing the overdraft. You will also note in the attached photo that the {$79.00} was posted to the account prior to a direct deposit of {$230.00} on the same day of XX/XX/XXXX. By posting the debit first rather than the deposit this also helped overdraft the account. 
Due to the backposting of this overdraft fee on XX/XX/XXXX it appears that XXXX more transactions over drafted my account again ( see attached photo with transactions in the amounts of {$5.00}, {$8.00}, and XXXX. When I spoke with customer service with KeyBank on XX/XX/XXXX I was informed by XXXX ( a manager ) that it was the customers responsibility to be aware of the funds available in the checking account and not to solely rely on the online banking ; I completely agree with him. However, if I am not informed of this overdraft fee being applied to the account, I am unable to account for this in my transactions. This overdraft fee did not reflect in the account transaction balance at ANY TIME on XX/XX/XXXX. In fact, I checking the account balance at approx. XXXX at which time I had {$16.00} and some change in the account. Then again at XXXX at which time I had roughly {$11.00} and some change. 
I would like for the posting practices of KeyBank to be investigated. I also dispute any over draft fees received after XX/XX/XXXX, other than the original {$37.00} charged on XX/XX/XXXX Because of how the bank chose to add this fee and backdate the time of posting without being informed, they will now recover more overdraft fees because I was not away they were going to debit these funds from my account.