In addition to the relationship between customers and invoices being inccorect, you are missing at least one table. Putting Platform in the Customer table implies that the customer only subscribes to one of the services you mentioned. I'm guessing that most customers subscribe to more than one service. Therefore, you need a separate table called tblCustomerPlatform. In that table you need intersection data because also, a customer's name may not be the same across all platforms. Therefore, you would put the CustomerName in the junction table that links Cusstomers with Platforms
As the others said, CustomerName does not belong in the details table, nor does it belong in Invoices. Hwever, Invoices needs CustomerID to relate to Customers
Your names are pretty good but you need to avoid reserved words. Two that are especially problematic are Name and Date. There's two ways to do this - either you memorize the names of all reserved words in the Access, VBA, and SQL Server lists or you use combpund names whenever the word is so simple and common that someone has already claimed it. For Name you could use FirstName and LastName since combining all the pieces of a name will cause other problems should you want to send people letters for example. You'd like to say Dear Par rather than Dear Pat Hartman or even worse, Dear Hartman, Pat. Keep in mind that it is always easier to concatenate the parts of a name or address than it is to split them. For the same reason I would split Address into Addr1, Addr2, City, State, Zip. The reason for splitting Address this way is so that you can create a proper label for printing that will pass muster with the postal service. Thinking that you can save time/space/whatever because you will NEVER, EVER have to do anything that requires the individual parts of name and address is shortsighted. Do it now so you never have to face the worse problem of splitting these fields later. If you're in the direct mail business, you go even much further with how you split address because you also need to eliminate duplicates so you separate out cumpass directions, street type designations, house numbers, etc. Plus you standardize them. South is always S and Road is always Rd etc.