The phrase "wast there for" is a variation of the archaic and poetic expression "was there for". The pronunciation of "wast" is /wɑːst/ which is the second person singular past tense of "be". It is spelled with an "s" instead of the modern "t" ending which is typically pronounced /wɑːstə/. The spelling "for" remains the same as the contemporary usage, and the phrase "wast there for" means "you were present for". This style of language is commonly found in classic literature or poetry.