Borders not showing up in Visual WYSWYG editor

Hello I am building a site where my client will have an inventory page, just like a spreadsheet of info on one of their pages. I want this to be as easy for them as possible. So I added a plug in that adds a table row/column editor to the WYSWYG so they can easy add more rows and columns to their inventory list.I added borders to the table so they can go in and very easily add the info into the row/column where it needs to go. The funny part is the vertical borders show up on the front end of the site but not in the Visual WYSWYG page in the backend! Errrrrr. The horizontal lines are there but the vertical lines are not showing up so they have to click all over the page to find out where the next column is!!! This will be way to hard for the client to use. I am a designer so I have changed the css for this div numerous times without success in the backend! Help!!

I also looked into some spreadsheet like plugins but I am not sure where to start. I do not need a store or shopping cart this is basically just for the owners of the site to put in inventory because they wanted it on their site!!!

Thanks so much!