Citibank Credit Card Complaint

Citibank Credit card department,

APR or interest rate Florida

I purchased a new washer and dryer from Home Depot and took out a new credit card issued by Citibank. The terms were any purchase of $1900.00 or more would be 24 months of no interest if paid in full. I contacted customer service on -/-/2017 and was told that they have me on 6 months of no interest. I asked the representative to make the correction to 24 months and they said they could not help me. I need this corrected to match the terms I agreed too and its the sole reason I opened the credit card.