Metro by T-Mobile

I went to this location, 7840 gerber rd, sacramento, ca 95828. To purchase a sim card upon arrival employee told me he can sell me one but another employee came from the back and said they are not allowed to sell sim cards it was something that had changed within 24 hours. I did ask for some thing in writing and was declined by the owner as he said he was is the owner. I m a 4th stage cancer patient took a ride from a friend and was told I cant get a sim card. I would like a investigation on this or I will take this to better business bureau..