Blocking a paid up account without notifying

I've had a credit card with AB for years Dec & Jan had a hiccup and missed payments and was still able to use the card.<br> <br> Suddenly out of nowhere they blocked my card without notifying me and I mean how do you do that??? where is the customer service and loyalty in that. I'm going crazy because the call center is not even giving me a constructive response.<br> <br> I've been using this card since then out of nowhere they just block it.<br> <br> This is truly annoying and then they send me an sms that I must send my documents to a branch but I was there yesterday!!! To do that no man we not your toys!!!!