Question

I am wondering if this is just a me problem but for some reason, Mercari does not allow me to counter offer any offer I recieve from seller. I am new to Mercari so I am not sure if it is something I can fix. An example is a seller would send me an offer for 18 but I cannot go lower because Mercari go by the original price they have posted for others which is 24 . If I want to counter offer 15, they would give me a screen saying I have to give offer between certain range but the range is like 18 - 25. I'm not sure why it is not using the offer price but is using the original price when I want to counter offer. It has always been using the offer price so I do not know if this is new for Mercari or it is just me. I'm also not sure on how to report this issue to Mercari since there is nothing on their website about this. Does anyone know how I can fix this issues or where to go to get Mercari help?