Contacting them about a particular domain might give them justification to renew it next year or whenever it expires. If you must call/email, see how much pricing information you can get from them without mentioning a domain name. And, if you must include your domain name, pretend like you are checking up on several domain names (list about 10 or so), that way, they have no clue which one is of value to you. Pretend like you really don't care about it, maybe you're just scouting around for prices but let the person gain your interest with a reasonable price.