Citibank Credit Card Complaint

Citibank Credit card department,

Late fee Vermont

Sears credit card : I mailed my payment in for the full amount of $22.00. The due date was -/-/16 ( a Sunday ). My payment arrived on -/-/16 ( a Monday ). My next bill showed a payment amount and a $2.00 interest charge. I was confused because under late fee it said $22.00, but I sent in my $22.00, so I sent in the $2.00 thinking that was because I was one day late. The next bill came and now it said I owed $48.00. I could n't imagine how so my daughter looked into it and we realized that they said I was late ( even though on this site it says that it should not be late if the mail is n't delivered on due date, and the payment arrives the next day ) AND that they had charged me a late fee of - % of my due amount ( $22.00 ) which was not only outrageous but confusing. So I called the account question phone number and they would n't do anything. In fact they tried to tell me that if the due date is Sunday I have to have it mailed there by Saturday. I have filed a complaint with them but am worried that they will continue to add charges OR if I pay it, they will not eventually reimburse me. Also, I ca n't imagine why their computers do not adjust for the due date on Sunday event where payments received by mail on the next day, Monday, should be considered on time, and therefore probably are illegally charging late fees to many people.