T-Mobile customer service

We misunderstood website and added what we thought was unlimited texting. We have had t-moble since 2003 and never had a problem with texting. Due to my own error we only added it on one line instead of all 4. T-mobile said since it was past the billing date they could not credit us. The supervisor on the phone was very rude and said we could never call them again since we were harrassing them. It took me till the middle of June (and 2 emails from me) to get them to post the bill in question. Of course I was not going to pay anything till I had a hard copy of the bill. I then went ahead and made 2 payments in July of over $300 dollars ( the bill was only $700) and tried to get them to make payment arrangments with me. The had told us originally we would be able to make arrangements but never would set them up with me. On the August 1, I went to the webite to make another payment and have now found out the have turned me over to collections even though I was paying date in payments as they told me I could. We never intended to defraud and run up a debt we did not intend to pay but T-Mobile is completely unwilling to help us or work with us.