This letting agent is by far the worst I have ever dealt with - they have a complete monopoly on the properties in the highly sought-after area of Jericho in North Oxford and as such, basically treat all their tenants like crap because they know they can always find other people to fill their properties.
They rarely answer the phone, and never call back when you leave messages. They make promises they can't keep, and are extremely unprofessional. When we moved in, our house was a mess. It was supposed to be professionally cleaned and instead all the cabinets were overflowing with old items left by the previous tenants, and there was a large pile of loose garbage and garbage bags in the middle of the living room. We cleaned it and got an assurance from NOPS that we would not have to get a cleaner at the end of our let. But come August, that assurance paper had mysteriously disappeared from our file, and they took £300 out of our deposit, even though we had cleaned the place from top to tail ourselves over a whole weekend! On top of that - there was mould all over the walls of one of the bedrooms, which they never cleaned even though we requested it multiple times throughout the year.
They are unreliable, unprofessional, completely incapable of doing their jobs properly, and to top it all off they clearly consciously cheat people out of money. I wouldn't use them again if they were the last letting agency on earth.