So this is said by the guy who's not delivering the goods and is being hassled by the other guy who needs them urgently. Given the context, Adrian's suggestion makes sense to me. It would be one of these meanings:
"relajar(se).
[...]
IV. 1. tr. Ur. Insultar a alguien. pop + cult → espon.
2. Ur. Criticar o reprender duramente a alguien. pop + cult → espon."
http://lema.rae.es/damer/?key=relajarseSort of "don't give me a hard time". "Hay mucha busca" would be an excuse for not yet having supplied the product. But it's marked as Uruguayan.
However, I wonder if it's more widespread than that. The writer of the following, in a Spanish football forum (about Basques not liking people calling Athletic de Bilbao "el Bilbao") is presumably Spanish:
"Podría relajarme a ti y escribir 5 lineas de insultos que seguramente te vengas cómo un guante pero no es plan."
https://m.forocoches.com/foro/showthread.php?t=3318445&page=...By the way, as this shows, the pronominal form (i.e., the "te") would fit in here.
It's surely not likely that the person being hassled for not producing the goods would be telling the other not to relax. He would be saying the opposite (as Robert has noted).