1.please accept our thanks for the trouble you have taken.
有劳贵方，不胜感激。 2.we are obliged to thank you for your kind attention in this matter.
3.we tender you our sincere thanks for your generous treatment of us in this affair.
4.allow us to thank you for the kindness extended to us.
5.we thank you for the special care you have given to the matter.
6.we should be grateful for your trial order.
7.we should be grateful for your furnishing us details of your requirements.
8.it will be greatly appreciated if you will kindly send us your samples.