DLC make me so angry

They have breached OFT guidelines by doing that,

Ring me continually demanding I pay more than I do presently.

2 UNFAIR BUSINESS PRACTICES
Communication
2.1 It is unfair to communicate, in whatever form, with consumers in an unclear,
inaccurate or misleading manner.
2.2 Examples of unfair practices are as follows:
f. contacting debtors at unreasonable times
g. ignoring or disregarding debtors' legitimate wishes in respect
of when and where to contact them, for example, shift workers who
ask not to be telephoned during certain times of the day
Physical/psychological harassment
2.5 Putting pressure on debtors or third parties is considered to be oppressive.
2.6 Examples of unfair practices are as follows:
a. contacting debtors at unreasonable times and at unreasonable intervals
f. pressurising debtors to pay in full, in unreasonably large instalments,
or to increase payments when they are unable to do so
g. making threatening statements or gestures or taking actions which
suggest harm to debtors

I should borrow money to pay of the remaining balance

2.5 Putting pressure on debtors or third parties is considered to be oppressive.
2.6 Examples of unfair practices are as follows:
b. pressurising debtors to sell property, to raise funds by further
borrowing or to extend their borrowing

I have asked for a statement of payments 3 times as I do not believe my ex has paid a penny towards this joint debt

2 UNFAIR BUSINESS PRACTICES
Communication
2.1 It is unfair to communicate, in whatever form, with consumers in an unclear,
inaccurate or misleading manner.
2.2 Examples of unfair practices are as follows:
e. failing to provide debtors or creditors with information on status
of debts, for example, not providing requested balance statements when
reasonably requested

It is worth noting that as a Joint debt, you are both liable for the full amount, if your OH doesn't pay they can chase you for it, if you don't pay they can chase him. As you are jointly responsible for the full amount there is no legal statement saying you only pay 1/2 back, if you pay 1/2 and he pays nothing, they will carry on chasing you both.
Good job on getting the fraud department to sort out his attempt at paying with your money

As to the telephone calls, they can be stopped. Read this post on removing your phone number from there system and complaining to them about harassment - http://forums.moneysavingexpert.com/showpost.html?p=11571485&postcount=4

Whilst you have sought advice from CAB< have you considered contacting National debtline, CCCS, or PayPlan. They all offer free professional advice on debt issue and could provide further assistance. If you have savings they might consider a final offer on the debt, if it is a large debt and you won't every beable to pay it off and have little assets bankruptcy maybe a possible route, but they would beable to advice further.