Lost an domain ? yahoo small business

Hi, few moths ago I registered an domain using yahoo small business service, it was some kind of giveaway of domains(it costed less than an buck for dot com domain). Everything was running smooth, until few days ago when I changed my hosting provider. I sucesfully transfered my files and sites to new host, but then it was time for me to change nameservers for that one domain registered with yahoo. I could not remember my login details for yahoo. So I sent mail(with admin mail adress for that domain-that adress is also in whois record) to damain dot tech at yahoo dot com asking them to change my nameservers. 5 days and still no answer... What shall I do ?

Call them. They have tech support number.

Emails are not always 100%. Maybe they didn't receive it.. It sometimes happens.