Unprofessional business/staff.
Staff only seemed attentive to email request for reservation but after receipt of credit card details, 1/ they never confirmed my reservation despite repeated requests, 2/ so I sent them a cancellation notice of the reservation 3 months prior to travel, 3/ yet they proceeded to bill my credit card for a reservation that never was.
They then feign problems with receiving cancellation notice from me despite my sending them copies of dated emails requesting such. They however could not provide me with similar evidence that they had ever responded with a confirmation. They still refuse to reverse the credit card charges.

My wife wrote to make a reservation. They never replied with a confirmation even after 3 follow-up emails. We decided to cancel, and requested a reply which they never answered. We stayed at the excellent Hotel Fita instead, and presumed that Monopole was a dead deal. When we got back to Canada, imagine our surprise when Hotel Monopole charged us a one-day, no-show room rate! After several email complaints, they sent a single reply in undecipherable English claiming that we didn't send them a proper fax number for them to confirm the reservation. You need a fax number to confirm an email reservation?!!! This Hotel Monopole is run by con artists, and destroys the wonderful image we have of Amsterdam.

Stayed in the room without a window. There is a bar next to it, they played loud music all night. We couldn't sleep for four nights. The hotel staff was rude and they just wanted the money ans didn't care about us not being able to sleep.
Don't stay in this hotel. Save yourself a headache.

The hotel is absolutely terrible. I gave them my credit card info to hold the reservation and then we paid in cash upon arrival. After we left the hotel charged my credit card 300 Euros for damage to the room-complete fraud! The whole room was damaged. DO NOT STAY HERE they will try to scam you.