Calling 978-753-5000 to reach Sylvania's customer service department is a mistake, because this is not a customer service number. This is actually the number for the North American headquarters of Ledvance, the parent company of Sylvania. As such, unless you happen to be looking for a specific employee of Ledvance or Sylvania, all you'll get from interacting with this number is an automated message.
If you do call this number, and the automated message asks you to dial your party's extension to be connected with them. Alternatively, you can ask for a dial-by-name phone directory that allows you to punch in the first few letters of their name. If you wait beyond this part of the phone menu, a voice tells you to dial 1-800-544-4828 for light bulbs or another part of customer service.
When you dial this number, a voice lets you know that Sylvania's customer service via this number is available Monday through Friday between 9 a.m. and 5 p.m. Eastern time, and it is not available on holidays, including the day after Thanksgiving.
A check of Sylvania's website confirms that the automated message is accurate and dialing 978-753-5000 doesn't provide customers with any service. To make things more complicated, there are multiple customer service options listed on the website, depending on what kind of customer you are. Sylvania does not sell directly to consumers, so its customer service calls are mainly directed at issues with the light bulbs themselves or questions on what retailers carry Sylvania products. For those retailers who buy directly from Sylvania, Leadvance offers a separate customer service line that isn't meant to be accessed by everyday customers.
Overall, I found the setup of this number to be business-like, with very little emphasis on the experience of the caller. Obviously, the business has had some issues with people dialing this number for customer service and appears to want to discourage people from dialing it. That's most likely so its workers can focus on dealing with the clients that do direct business with Sylvania.
Otherwise, calling this number isn't going to get you any answers to your customer service questions. Unless you're unsure of what the actual customer service number is at Sylvania and this is the only number that you can find. For all other customers, you'll need to check Sylvania's website and locate the correct customer service number to get the assistance you need.