Martenity benefit

I'm still waiting for my martenity benefit from May until now in August and I'm going back to work in a weeks time with not a single payment from them. They send me from pillar to post. At first it was the surname issue, they were picking up my ****en name instead of my marriage surname. They've changed the surname on their surname and it took. Ore than a week. After that I went for re-issue and it's almost 2 weeks I'm still waiting for payment.who are supposed to send our complains to?