NO HELP AT ALL

I have been having trouble using my credit card for about a month now, I tried calling and they said I have to email all details to an email address, NO one sees any problem with my card or account!! HOW AM I SUPPOSE TO USE MY CARD NOW! Theres def something wrong if it doesn't want to work on 4 different online purchases! then they say its the app its the app, ITS NOT WORKING ON 4 different apps how does that make sense then??? The card doesn't work ANYWHERE!!! and NO one can help me?? soo what am i suppose to do now