The unnamed family were due to stay in the town for the annual music spectacular which takes place this weekend.
But they were forced to find a hotel at the eleventh hour after they were told the Home Office had taken over the Mercure George Hotel to house refugees.
They had booked two rooms at the hotel for this Saturday, according to BerkshireLive.
The family’s mum said they make the bookings a year ahead of the event, and then cancel if they decide not to go.
But just days before the event - which will see huge numbers of people book to stay in the town - all the bookings were cancelled.
The family have managed to secure new accommodation, but the hotel is out of town, which means one of their family members will have to drive into the centre and back instead of being able to walk.
She said: "Experience says it's impossible to get taxis when the festival is on, so one of us will have to not drink for the day and park in one of the local multi-storeys.
"It sounds incredibly privileged and makes me feel quite uncomfortable to complain about this.
"I know what these people are going through is thousands of times worse than us losing our hotel booking. But at the same time, I feel the bookings should've been honoured.
"At this time of year, most of the people there would've been only there for this weekend."
An email sent to the family on Sunday, August 22, read: "We are sure you have been watching the recent turn of events with horror and disbelief and maybe have at times thought if there was some way to help them.
"As the scale of the crisis in Afghanistan grow, the Home Office are struggling with the number of refugees to re-home.
"They have started to reach out to local authorities to ask for help within their communities for housing.
"We have been approached by the Home Office to house these people, after much deliberation we have agreed to house these people for the interim.
"We have not taken this decision lightly and know the effect it has on you and your plans, however we feel it was the right decision to make in view of the humanitarian crisis facing these people.
"We have been looking forward to your stay at the Mercure George, however due to a turn in circumstances as advised above we have to request you to look to make some alternative arrangements.
"We do hope and are sure that our guest - you - will help us support these people in these dire times and understand our dilemma."
The government has confirmed it will take 20,000 Afghan refugees over the next four years - around 5,000 a year following the country’s takeover by Taliban.