Please help me with tenses

Could anybody please check if I used the tenses correctly in the passage below. Many thanks in advance.
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You have just kindly advised us that you had to buy machines of another company. We are sorry that your order was placed with our competitors because our delivery time was not suitable to you and you found our prices too high.

We would like to explain to you first that we are very heavy with orders now and the deliveries as a result extend. Besides, some modifications have been made in the machines to achieve higher capacities. That is why our prices are higher than our competitors’ prices.

Nevertheless, we feel that if you had taken into consideration the high quality of our machines you would have agreed that they were priced reasonably.

We hope that you will be able to place your future orders with us.

[Mister Micawber]

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Change 'extend' to 'have been delayed'.
Change 'you had taken' to 'you take'; and 'you would have agreed' to 'you would agree'; and 'were' to 'are'.

All your other verb tenses are fine.
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