Are these sentences correct??
1. Today we got a complaint from a customer.
2. According to the customer, they cannot install our products on their machines because the holes on our products to install on their machines are a little smaller than what they demanded/ordered/asked for.
3.They can install our competitors' products on their machines very easily (smoothly?).
4. We researched our products and discovered but found out that there was nothing wrong with them.
5.In addition to it, it turned out that the specification on the order of the products, which are complained now, is totally exactly the same as what we have been supplying supplied to this for the customer for a long time and they have never complained until now.
6. In spite of this of it, it is very weird why that the customer cannot easily install easily only the products which we recently supplied. on their machines.