There are 6 'yous' in Spanish. Each 'you' requires its own separate, individual verb conjugation in ALL tenses, not just the past tense - the tense to which this query refers. Here are the answers to this seemingly 'simple' question.
You, familiar singular:
No contestaste el teléfono. (could be TÚ or VOS in spanish America, the latter especially in Argentina, Uruguay, Paraguay and Central America):
(Tú) no contestaste el teléfono.
(Vos) no contestaste el teléfono (Argentina, Uruguay...).
You, formal singular:
Usted no contestó el teléfono.
You, formal plural:
Ustedes no contestaron el teléfono.
You, familiar plural:
No contestasteis el teléfono.
You, affected singular (but this sort of "voseo" is only found in poetry or religious texts, since it belongs to classical Spanish. Thus, nowadays you won't ever find an expression like: Vos no contestasteis el teléfono, because telephones were not invented yet.
There are several different ways to answer the phone in spanish. In many countries, you simply say "¿Aló?" Other options are "Dígame," "Diga," or "¿Bueno?"
Make a phone call - haga una llamada de teléfono
Hello?
Telefono
condenado telefono
celular or móvil
Tele'fono mo'vil
my phone has died = mi teléfono ha muerto
no tango una telephono.
Estoy en el telefono
Spanish teléfono celular
Try: teléfono celular
Por una llamada telefónica.
depends what the number is for...phone, math, ..etc
Todavía / aún no tengo teléfono.