Cannot use my DFS account number

I got approved for the line of credit of DFS. I can access to it and everything. but at the moment to checkout says that my account cant be found. It is just time consuming and frustration. My expectations of using Dell's Services was very high and now I can see the reality. I have a line of credit active but I cant use it. It is like buying a car and you can not drive it. And nobody gives me a solution to this matter. I don't recommend applying for Dell Financial Services, It is a pain to deal with everyone on the phone. They do not even write notes of what happened every time I called and you have to explain everything over and over again just to get the same negative outcome. Not recommendable at all.