United Airlines issued an apology to a female passenger and gave her a $500 travel voucher after her first-class seat was allocated to a Congresswoman due to preferential treatment, as stated by an airline official Monday.

John-Marie Simon, 63, from Washington D.C., accused the airlines' saying that her seat was given to Representative Sheila Jackson Lee.

The airline officials claimed their internal systems showed that Simon had canceled her trip after there was a weather delay. However, Simon denied this doing this, a New York Post report stated.

According to a spokesman for United Airlines, the company issued an apology to Simon and also offered a voucher in a bid to correct the wrongdoing.

However, Simon, in a tweet, claimed that the corporate office of United Airlines did not issue an apology. Instead, an employee of the airlines who attended to her complaint apologized to her.

She also stated that the apology she received was far off from the apology which the airlines' owes her.

Simon, in another tweet, stated that the $500 voucher was not part of the “apology package” and that she was offered the voucher by an “exasperated” agent who earlier offered her a $300 voucher.

According to a report by Houston Chronicle, Simon used 140,000 miles to purchase a first-class ticket from United Airlines on Dec. 3 for a flight from Washington D.C. to Guatemala and back.

The report further stated that during the last leg of her home-bound flight, at George Bush Intercontinental Airport, Houston, an agent at the boarding gate scanned her ticket and informed Simon that her trip was not registered in the system. This incident took place after an hour-long delay to the flight due to weather conditions.

Simon posted a tweet with a picture of Lee sitting in the seat which was assigned to her. She stated that the airlines gave her seat away without notifying her and also without her consent.

In another previous tweet which Simon posted, she stated that according to another Congressman who was traveling with her on the flight, this incident was not an isolated case with regards to Lee. The congressman told Simon that he had seen Lee do the same on two previous occasions.

The flight attendant reportedly asked Simon: “Did you cancel your flight?” to which she replied, “No. I just want to go home.”

The report further stated that her seat 1A was taken by Lee and she was moved row 11 in Economy Plus class.

Simon posted a tweet with a picture of Lee sitting in the seat which was assigned to her. She said the airlines gave her seat away without notifying her and also without her consent.

With regards to the whole incident, Lee in a statement, said: “Since this was not any fault of mine, the way the individual continued to act appeared to be, upon reflection, because I was an African American woman, seemingly an easy target along with the African American flight attendant who was very, very nice.”

“This saddens me, especially at this time of year given all of the things we have to work on to help people. But in the spirit of this season and out of the sincerity of my heart, if it is perceived that I had anything to do with this, I am kind enough to simply say sorry,” added Lee.

In a Facebook post last Wednesday, Simon wrote: “The second agent asked the other agent if I was late coming in from another flight or another airline. The first agent told him no, that I had been on United, that my first segment had arrived three hours earlier, and that I had been at the gate.”

She further stated: “Then the second agent told me that perhaps I had canceled my own reservation. I said that was impossible: I had a boarding ticket in hand and I just wanted to get home. Then he told me that ‘united.com [United Airlines]  has changed your reservation’ and there was nothing United could do about it. ”