Account Deactivated Without Prior Warning

I contacted RCS call centre this morning. They informed me that because my account is new and I have not used it in the past 6months that it has been deactivated. I have had the account since 2013 and used it many times. The balance has been 0 since the beginning of the year and I have not needed to use it. I have never received communication that the account will be deactivated if I dont use it and even received a letter last week from RCS stating my available balance and encouraging me to use my card. This morning I called to update my address and was told that I cannot use my account and will have to apply for a new one from scratch. I use the account for necessary big purchases so that I can pay it off. For my account to be deactivated without my knowledge or any prior warning is ridiculous. It seems like I am being punished for paying my account consistently, maintaining a 0 balance and keeping myself in the green with the amount of credit I have against my name. I havent had 1 good experience with this company and will not be applying for another card.