how to organize the output of MLE using R - r

Question

I wrote down this function for MLE estimation and then I apply it for different settings of parameters.
Finally, I bind all results for an output.
But is not working i have problem with the output and also I need to organize the output like the attached image using R program.
enter image description here
could some one help me please?
What should I fix and how can I print the results like the picture attached.
thank you in advance
rbssn<- function(n,alpha,beta)
{
if(!is.numeric(n)||!is.numeric(alpha)||!is.numeric(beta))
{stop("non-numeric argument to mathematical function")}
if(alpha<=0){ stop("alpha must be positive")}
if(beta<=0) { stop("beta must be positive") }
z <- rnorm(n,0,1)
r <- beta*((alpha*z*0.5)+sqrt((alpha*z*0.5)^2+1))^2
return(r)
}
#Function
mymle <- function(n,alpha,beta,rep)
{
theta=c(alpha,beta) # store starting values
#Tables
LHE=array(0, c(2,rep));
rownames(LHE)= c("MLE_alpha", "MLE_beta")
#Bias
bias= array(0, c(2,rep));
rownames(bias)= c("bias_alpha", "bias_beta")
#Simulation
set.seed(1)
#Loop
for(i in 1:rep){
myx <- exp(-rbssn(n, alpha, beta))
Score <- function(x) {
y <- numeric(2)
y[1] <- (-n/x[1])*(1+2/(x[1]^2)) - (1/(x[2]*x[1]^3))*sum(log(myx)) - (x[2]/(x[1]^3))*sum(1/log(myx))
y[2] <- -(n/(2*x[2])) + sum((1/(x[2]-log(myx)))) - (1/(2*(x[1]^2)*(x[2]^2)))*sum(log(myx)) + (1/(2*x[1]^2))*sum(1/(log(myx)))
y
}
Sin <- c(alpha,beta)
mle<- nleqslv(Sin, Score, control=list(btol=.01))[1]
LHE[i,]= mle
bias[i,]= c(mle[1]-theta[1], mle[2]-theta[2])
}
# end for i
#Format results
L <-round(apply(LHE, 1, mean), 3) # MLE of all the applied iterations
bs <-round(apply(bias,1, mean),3) # bias of all the applied iterations
row<- c(L, bs)
#Format a label
lab <- paste0('n= ',n,';',' alpha= ',alpha,';',' beta= ',beta)
row2 <- c(lab,row)
row2 <- as.data.frame(t(row2))
return(row2)
}
#Bind all
#Example 1
ex1 <- mymle(n = 20,alpha = 1,beta = 0.5,rep = 100)
ex2 <- mymle(n = 50,alpha = 2,beta = 0.5,rep = 100)
ex3 <- mymle(n = 100,alpha = 3,beta = 0.5,rep = 100)
#Example 2
ex4 <- mymle(n = 20,alpha = 0.5,beta = 0.5,rep = 100)
ex5 <- mymle(n = 50,alpha = 0.5,beta = 1,rep = 100)
ex6 <- mymle(n = 100,alpha = 0.5,beta = 1,rep = 100)
df <- rbind(ex1,ex2,ex3,ex4,ex5,ex6)
Any help will be appreciated.