Macbook pro 2011 won't charge after adapter and battery replacement.

• My 2011 Macbook Pro recently had a RAM problem (black screen and and an intermittent alarm every time the power button was pressed), I took it to the local Apple genius bar, an assistant in ten minutes sorted the issue and it was turning on as normal. HOWEVER, before this problem occurred and even when it was occurring, the laptop still charged successfully as expected.
• Since taking my laptop home that day, delighted I could use it again, the adapter light remained green and did not go orange to indicate it was charging. I checked the adapter, notice a break in the wire and frayed cables on the inside so ordered a new one and figured that would fix it. New adapter arrives and the light still remained green on connection, so I figured it was an internal issue.
• Took it back to the genius bar and all they did was diagnose the battery in front of me, showing me the battery was actually fine but had gone over it's charge cycle lifespan, so I gave in and ordered a new battery as per the advice of the guy in the shop and a couple of tech friends of mine.
• New battery arrives IDENTICAL to the original one, I follow all the advice and tutorials online I could find to replace it and felt confident all was well. I put it in and the moment I connected the charge adapter it came to life and was in perfect working order.
• YET the adapter light is STILL GREEN and wont charge my Macbook, resetting the SMC and all the other suggestions given online, I believe it's an issue between the port and the battery internally but the people at the Apple store basically said that it's in good condition for it's age but couldn't help me beyond that. Like wtf?? It's obviously not the adapter or the battery itself, so WHAT IS IT???!!!

I'm living on the breadline here and NEED my computer, this Macbook works fine and it's this tiny issue, I've seen other people come forward with a similar problem but couldn't find any answers, pls help.

I think what annoys me most is that I've spent nearly a hundred quid trying to sort out the issue even though it wasn't an issue at all before I brought it to the Apple store...ever since I got the RAM fixed, the charging issues started, which I mentioned when I was talking to them the second time and they just blamed the age of the computer. If anyone had the same problem and resolved it, would be great for some helpful advice.