The problem is in trying to translate poetry, because poetry often isn't grammatical. There is a great deal of room for a poet to stretch or even break the normal rules of grammar - part of the so-called 'poetic license'. All the usual grammar rules get tossed out the window when writing poetry.
This makes poetry especially difficult to translate. You sometimes have to sacrifice rhymes, puns, or other wordplay to translate the sentiment.
With that in mind, you should translate the poem however best keeps the expressed sentiment and meaning. You won't be able to translate word for word.
Take a look at the two different translations you've already given. They aren't identical in meaning.
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''Love God if you want to. You will not get faithfulness from the toys (here means ''human beings'') made of clay'' correct?'
This seems to express an idea that it makes no difference if you love God, since humans won't be loyal or faithful to other humans regardless.
To me, I don't quite get the connection between loving God, and the tendency of humans to not be loyal to each other. I don't see the connection between human-human and human-God relationships.
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''Love only God if you want to,
You can't get fidelity from toys (referring to humans) made of clay''
Here you've added 'only'. This version to me suggests that perhaps it's only worth loving God, because humans won't love you back. Now there's a clear relationship between the suggestion as to why you should love God, and not humans. It's stating that only God will be faithful, return the love, etc. Human-human relationships are wasted, and human-God relationships are requited.
You need to look at what ideas or sentiments the poem is expressing in the original language, and translate those.
If you have any problems with it, you can post back and get some suggestions or feedback. Keep in mind though, that since this is poetry, the most accurate translation into English may not necessarily be grammatical English, which is perfectly acceptable for poetry.
