dont fall for the "free line"

same experience.  I ported my 9$ a month landline to T-Mobile because it was free. Then the bill shows up. I call the customer service they say it will take a billing cycle or two for the line to become free and they give credit. Then I am charged again the second month so again call to customer service they give me credit.  3rd month charge again this time customer service says the promotion was over when you got the 3rd line so go to the store.  Store says they are wrong your third line should be free and give me store credit and they said it should be free on the next billing cycle.  I ask store manager to add the not of 3rd line to be free as memo on my account and I take picture of it.  4th month billed again the store manager says we made a mistake by telling you incorrect offer. Gives store credit and says he will add it every month. 5th month billed again. No store credit. Go to the store the manager doesn't remember anything. I show him his memo so he adds the credit.  6th month billed again I go to store he says their system crashed so he could not add the credit and then adds the store credit.  Monday will be the 7th bill. What a  scam t-mobil is running.