Inspiron 15 5567 Battery Replacement & Cost

Good day to all members. 

So I have this Dell Inspiron 15 5567 since mid 2017, the battery has started to bloat to the point it's pushing up my touchpad, so I'm thinking of replacing it before anything bad happened. I'm from Indonesia and sadly they said we have no authorized service centers, some authorized dealers I've contacted also ended up with no response at all when I asked if they could help me order the battery. 

After I browsed here and there, I see lot of other users also had this problem (dying battery but no available replacement). So I'd like to ask :

1. Does Dell really don't sell the 'original' replacement parts?

2. If so, can we remove the battery and just keep it plugged it since it's not the simple, removeable battery? (I don't want to risk my notebook by keeping it inside, the laptop itself is still working very well)

3. Or is it better to buy and replace it with a knockoff instead? (I saw some local sellers selling the battery for around $50 but I'm not sure that's a genuine one since usually they'd cost $100?)

Thank you in advance and sorry for any mistake! English is not my first language