Complaint sub-issue: Trouble with how payments are being handled

I have about half of my student loans with Great Lakes. I am always checking on my loans so I can keep up with them. My payments are right around XXXX per month and I also have private loans with another lender also reaching XXXX per month. At XXXX per month just to make my minimum payments I am limited in what I can afford ( transportation, housing, etc. ). I read as much information as I could on ways to pay down my debt quickly without putting myself at risk for not having money for food and other basic living expenses. On the great Lakes website they discuss excess payments and how they are allocated. 
First off the website states that any over payments will be automatically applied to your loans with the highest interest. 
That's great. 
Except that is exactly what wasn't happening on my loans for almost 9 months. I thought okay shame on me for not noticing this. Time to do something about it. 
So I found on the website where I could choose which loans received the excess payments. Perfect. I chose, to start, my two loans with the highest interest both at 6.8 %. Around the same time I was eligible with my employer to start receiving assistance from them on said monthly payments. So now with my monthly payment of XXXX my employer was sending XXXX automatically every month. Such a relief. After one or two payments from both my employer and I, I checked online and noticed that their payments were putting me ahead. Great. But I also noticed that the two loans I chose were still not receiving excess payments. I called into the service center for great Lakes and the associate I spoke with agreed that it should've had any excess just on two out of my XXXX loans with them. She said she would put it in a request. Later that day all was well the amounts were adjusted. I went about paying those loans as usual and kept an extra eye on any excess payments. 
Again I noticed that when a payment from my employer came in after a full payment made by myself the excess was applied evenly to all loans. So again, not only against what I manually selected but also against what the website claims it will automatically do. Now I call again expecting a similar outcome as before. This time I'm placed on hold multiple times for almost a half hour total. The associate then comes back with an explanation that is so long and convoluted that not only was I confused but I felt the person working for great Lakes was completely unsure of what he was telling me. During this call a part of the explanation included telling me my extra payments were essentially in a " holding account '' and wouldn't be applied until my next payment was due. Infuriated I hung up. Not only did I feel that I was speaking to someone who was not confident in what they were telling me but also making up what I hoped were just examples to help understand the excess payment method. I called again later that day and spoke with another associate. I explained briefly my situation and what I had been told and she agreed with the first rep ( surprise ). Calmer this time I said okay what he explained did not make sense to me, can YOU explain it better so I can understand? 
She went on to fumble over her own words and again I received an over complicated explanation that left my head spinning. I said to her that what she said was still not making any sense. So to help myself understand I asked her this. 
" Ok. Currently the website says I am paid ahead until XX/XX/XXXX. On XX/XX/2018 it currently says I will then owe 70 ( and some change ). We are currently in XXXX. So this means my full month of XXXX is also paid. Yes? '' She tells me yes. 
" So, here is my question. If I pay for example XXXX $ right now. And of course given any interest will come off that amount first. But can you tell me approximately how much will go to the two loans I have selected to receive any excess? '' She was quiet for a while and was clearly trying to calculate this. Then finally she comes back to me with okay if you paid 100 ( keep in mind we were still in XXXX and I was paid ahead until XX/XX/XXXX ) then XXXX ( and some change ) will go towards the XXXX loans. 
So I asked why. 
She said oh the XXXX from here and then this that and the other thing. 
So I say " do you understand my confusion? We are NOT even in XXXX yet. And you are telling me even if I make a SECOND excess payment in XXXX ( because both myself and my employer had already made payments in XXXX ) that because of the amount you are saying I do not owe until XX/XX/XXXX only XXXX will go to the XXXX loans? 
She responded with oh. And then more silence. 
I never received a solid confident answer and did my own research between the XXXX calls. The website 's example of excess payments is expained exactly how I would think they would work. Yet somehow these phone reps are trained to over complicate and confuse the answer. 
I plan on calling again and speaking with a manager because I also work in a call center and maybe this is what they are trained to tell you. But it is not matching up to what the website says and also to just basic logic. 
I've seen similar complaints on excess payments and am frustrated that my {$23000.00} loan will end up adding up to almost double that in what I pay. I am young and struggling to even live on my own because of this. Every tiny thing I can do to impact how much I ultimately pay on these loans matters and makes a difference. 
The overall student loan/debt situation we are currently in is so disappointing and disheartening that I constantly question why I went to college.