I was re-classified to a lower pay scale ,but I am still doing the exact same job as before.

HR called me into the office to tell me that due to a reorganization in the company due to lack of work I would be reclasifeid to a lower clasification ( From Material Handler A to Material Handler B) wich meant of course came with a lower pay scale of about 10% less,It had never happened in my Department;it is usual in Production Department from Operator A to be reclasiffied to B, but in their case the responsabilities and work decreases, along with the pay rate,not in my case I am still doing the exact same activities I did before in fact it had been modified shortly before this happened to increase the workload,I found out later by talking to some other workers, that I was the only person in the Company to be reclassified ,I am senior to another material handler in the 2nd shift ( I work 1st) yet he kept the classification and pay rate, do I have a claim? If so ;over what ,thank you